Methods of making a lithium mixed metal compound by reaction of starting materials are provided. The methods can include reacting and/or processed reacted starting materials to form the lithium mixed metal compound in the presence of a fluorine rich atmosphere or media.
H01M 4/1315 - Electrodes based on mixed oxides or hydroxides, or on mixtures of oxides or hydroxides, e.g. LiCoOx containing halogen atoms, e.g. LiCoOxFy
H01M 4/13915 - Processes of manufacture of electrodes based on mixed oxides or hydroxides, or on mixtures of oxides or hydroxides, e.g. LiCoOx containing halogen atoms, e.g. LiCoOxFy
H01M 4/58 - Selection of substances as active materials, active masses, active liquids of inorganic compounds other than oxides or hydroxides, e.g. sulfides, selenides, tellurides, halogenides or LiCoFySelection of substances as active materials, active masses, active liquids of polyanionic structures, e.g. phosphates, silicates or borates
H01M 10/0525 - Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodesLithium-ion batteries
2.
Methods for Preparation of Electroactive Lithium Mixed Metal Materials for High Energy Density Batteries
Methods of making a lithium mixed metal compound by reaction of starting materials are provided. The methods can include reacting and/or processed reacted starting materials to form the lithium mixed metal compound in the presence of a fluorine rich atmosphere or media.
An electrochemical storage cell may comprise first and second electrode sheets wound around a cylindrical core forming a jellyroll structure, the first and second electrode sheets each comprising uncoated conductive edges parallel to end faces of the jellyroll structure, and coated opposing surfaces between the uncoated conductive edges, first and second separator sheets mechanically and electrically separating the coated opposing surfaces of the first and second electrode sheets and mechanically and electrically separating the cylindrical core and the coated opposing surfaces of the first electrode sheet, and slotted cutouts from the uncoated conductive edges, the slotted cutouts angularly co-located relative to the cylindrical core upon forming the jellyroll structure.
H01M 10/0587 - Construction or manufacture of accumulators having only wound construction elements, i.e. wound positive electrodes, wound negative electrodes and wound separators
H01M 10/04 - Construction or manufacture in general
09 - Scientific and electric apparatus and instruments
Goods & Services
Batteries; Batteries for vehicles; Batteries, electric, for vehicles; Battery power supplies for medical ventilators; Electric batteries; Electric batteries for powering electric vehicles; Electrical cells and batteries; Electrical storage batteries; Lithium ion batteries; Lithium phosphate batteries; Lithium secondary batteries; Rechargeable batteries; Rechargeable electric batteries
5.
Cylindrical electrochemical cells and method of manufacture
An electrochemical storage cell may comprise first and second electrode sheets wound around a cylindrical core forming a jellyroll structure, the first and second electrode sheets each comprising uncoated conductive edges parallel to end faces of the jellyroll structure, and coated opposing surfaces between the uncoated conductive edges, first and second separator sheets mechanically and electrically separating the coated opposing surfaces of the first and second electrode sheets and mechanically and electrically separating the cylindrical core and the coated opposing surfaces of the first electrode sheet, and slotted cutouts from the uncoated conductive edges, the slotted cutouts angularly co-located relative to the cylindrical core upon forming the jellyroll structure.
H01M 10/0587 - Construction or manufacture of accumulators having only wound construction elements, i.e. wound positive electrodes, wound negative electrodes and wound separators
H01M 10/0525 - Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodesLithium-ion batteries
H01M 10/04 - Construction or manufacture in general
09 - Scientific and electric apparatus and instruments
37 - Construction and mining; installation and repair services
38 - Telecommunications services
39 - Transport, packaging, storage and travel services
41 - Education, entertainment, sporting and cultural services
42 - Scientific, technological and industrial services, research and design
Goods & Services
Apparatus and instruments for accumulating and storing
electricity; batteries; electric and galvanic cells;
electric cells for storage of energy; anode batteries;
lithium ion batteries; rechargeable batteries; batteries for
vehicles; rechargeable electric batteries; computer programs
(software) for the transmission of data in the energy
sector; charging stations for electric vehicles, electric
apparatus, and rechargeable equipment; charging appliances
for rechargeable equipment; software for optimization and
distribution of energy sources; apparatus for measuring,
monitoring, analysing and distribution of electricity;
apparatus for recording, monitoring, processing and
transmitting data; energy regulators; electric control
devices for energy management; apparatus and instruments for
accumulating, storing, controlling, distribution, transport
and regulating electricity; uninterruptible electrical power
supply (UPS); electronic control apparatus for energy
management; electronic control apparatus for data
management; apparatus and instruments for accumulating,
storing, controlling, distributing, transforming and
regulating electricity; apparatus and instruments for
recording, storing, transmission, processing and
reproduction of data; measuring and checking apparatus and
instruments; apparatus for recording, transmission or
reproduction of data, sound or images; monitoring
instruments; monitoring apparatus and instruments; voltage
monitors; voltage monitor modules; electric accumulators;
accumulator boxes; solar batteries; portable power supplies;
battery chargers; integrated circuits; cathodes; capacitors;
battery jars; cell switches for electricity; computer
application software for use in implementing the internet of
things (IoT). Installation, maintenance and repair of energy saving
apparatus; installation, maintenance and repair of apparatus
for regulating energy; installation, maintenance and repair
of apparatus and installations for the storage and
distribution of energy; installation, maintenance and repair
of machinery for generating electricity; servicing of
apparatus for supplying and distribution of electricity;
providing information relating to the repair or maintenance
of energy storing, accumulating and regulating apparatus and
instruments; installation, maintenance and repair of power
generators; construction, assembly services relating to the
installation and maintenance of energy transforming
installations and apparatus, energy distribution systems and
apparatus and energy accumulation and storing installations
and apparatus; construction of energy networks;
construction, assembly services relating to the installation
and maintenance of energy and/or electricity charging
infrastructure and apparatus as well as energy and/or
electricity charging stations and apparatus; repair,
maintenance and construction of high-voltage and
medium-voltage electrical installations; leasing and rental
of energy charging infrastructure, energy charging stations
for charging batteries and battery chargers. Electronic data exchange; data transmission in order to
manage assets and resources efficiently; electronic data
interchange services; computer communication and internet
access; communications via computer terminals; electronic
communications services and providing access to electronic
communications networks, wireless communications services;
providing access to off- and online platforms for sharing
knowledge and information; communication of data and
information via computer networks, computing devices,
Internet, mechanical machines and devices and digital
machines and devices (internet and internet of things (IoT))
relating to the efficient management and allocation of
energy, assets and resources; leasing and rental of
apparatus for transmitting data; leasing and rental of
apparatus for transmission of data, sound or images. Storage of energy; information and advisory services in
relation to the distribution of energy; distribution of
energy; storage, distribution transport and transmission of
electricity; electricity supply and distribution services;
leasing and rental of devices, apparatus and instruments for
the storage, transmission and transport of electricity and
energy, namely leasing and rental of energy storage
products, batteries, electric, galvanic cells, electric
cells for storage of energy, anode batteries, lithium ion
batteries, rechargeable batteries, batteries for vehicles,
rechargeable electric batteries, apparatus for distribution
of energy, energy regulators for storage and distribution of
energy, electric control devices for energy storage,
apparatus and instruments for accumulating, storing,
controlling, distribution, transport and regulating
electricity, uninterruptible electrical power supply (UPS),
control apparatus and instruments for storing, distribution,
transport and regulating electricity and energy, voltage
monitors, voltage monitor modules, electric accumulators,
accumulator boxes, solar batteries, portable power supplies,
integrated circuits, cathodes, capacitors, battery jars,
cells witches for electricity and the use of power lines to
third parties; providing information and advice in the field
of transport, storage and distribution of energy and
electricity; consultancy in relation to the storage and
distribution of energy and electricity; consultancy in the
field of efficient allocating of energy storage,
distribution and supply; providing information and advice on
the storage and distribution of energy; leasing and rental
of apparatus for storage, transmission and transport of
electricity and energy. Leasing and rental of apparatus for recording or production
of sound or images. Technical design services relating to the use of different
types of electronic data collection; design and development
of software containing and able to provide information
relating to energy and energy efficiency; providing
technical information relating to energy efficiency and
energy saving; technical, scientific and industrial research
in the field of "smart cities"; design and development of
energy distribution networks; design and development of
software for the efficient management, distribution and use
of assets and resources; design and development of software
for control, regulation and monitoring of energy systems;
design and development of energy generation systems;
development of systems for energy management and electricity
management; computer programming for energy distribution and
management; programming of energy management software;
technological consultancy in the field of energy storage and
energy use; engineering in the field of energy technology
and energy supply and transport systems; conducting
measurements in the field of energy and energy use,
distribution and consumption; design and development of
computer software for energy management; consultancy in the
field of energy efficiency; leasing and rental of computer
programs (software) for the transmission of data in the
energy sector, software for optimization and distribution of
energy sources, measuring and checking apparatus and
instruments, monitoring instruments, monitoring apparatus
and instruments, and computer application software for use
in implementing the internet of things (IoT); leasing and
rental of apparatus for analysing of technical data.
09 - Scientific and electric apparatus and instruments
Goods & Services
(1) Lithium cells and modular batteries for utility energy storage, renewable energy storage, power grid frequency regulation, peak power shaving for industrial and commercial power consumers, distributed energy storage (DES), community energy storage (CES), solar energy storage batteries, wind energy storage batteries, high rate uninterruptible power supplies, electric vehicle batteries, namely high end motor sports, electric trucks, electric city delivery vans, automotive batteries, electric trains, electric-buses, auxiliary power for fire trucks, DC electric motors for machines, electric lift trucks, automated guided vehicle batteries, industrial robot batteries, electric aerial equipment and personnel lifts, DC power for marine electric motors, namely, electric tug boats, electric ferries, electric yachts, and electric boats, telecommunication hut battery back-up, aerospace batteries, aviation batteries, electrically powered mobility scooters, auxiliary power units, medical equipment and devices, namely ventilators, suction machines, infusion pumps, defibrillators, portable EKG and EEG machines, ultrasound machines, industrial and commercial hand-held power tool batteries, military auxiliary power, namely electric power generators, emergency detection & surveillance, namely fire alarms, gas alarms, anti-intrusion alarms, emergency lighting, street lighting, safety indication signage, and general purpose DC power
09 - Scientific and electric apparatus and instruments
Goods & Services
(1) Lithium cells and modular batteries for utility energy storage, renewable energy storage, power grid frequency regulation, peak power shaving for industrial and commercial power consumers, distributed energy storage (DES), community energy storage (CES), solar energy storage batteries, wind energy storage batteries, high rate uninterruptible power supplies, electric vehicle batteries, namely high end motor sports, electric trucks, electric city delivery vans, automotive batteries, electric trains, electric-buses, auxiliary power for fire trucks, DC electric motors for machines, electric lift trucks, automated guided vehicle batteries, industrial robot batteries, electric aerial equipment and personnel lifts, DC power for marine electric motors, namely, electric tug boats, electric ferries, electric yachts, and electric boats, telecommunication hut battery back-up, aerospace batteries, aviation batteries, electrically powered mobility scooters, auxiliary power units, medical equipment and devices, namely ventilators, suction machines, infusion pumps, defibrillators, portable EKG and EEG machines, ultrasound machines, industrial and commercial hand-held power tool batteries, military auxiliary power, namely electric power generators, emergency detection & surveillance, namely fire alarms, gas alarms, anti-intrusion alarms, emergency lighting, street lighting, safety indication signage, and general purpose DC power.
13.
RECHARGEABLE BATTERY MODULES AND RECHARGEABLE BATTERY MODULE HANDLING METHODS
Rechargeable battery modules and rechargeable battery module handling methods are described. According to one aspect, a rechargeable battery module includes a housing, a plurality of terminals, a plurality of rechargeable cells within the housing and coupled with the terminals, and wherein the rechargeable cells are configured to store electrical energy, a plurality of lift members at different locations of the housing, and wherein the lift members provide a plurality of lift points for the rechargeable battery module which enable the rechargeable battery module to be lifted in a plurality of different orientations.
An electrochemical storage cell may comprise first and second electrode sheets wound around a cylindrical core forming a jellyroll structure, the first and second electrode sheets each comprising uncoated conductive edges parallel to end faces of the jellyroll structure, and coated opposing surfaces between the uncoated conductive edges, first and second separator sheets mechanically and electrically separating the coated opposing surfaces of the first and second electrode sheets and mechanically and electrically separating the cylindrical core and the coated opposing surfaces of the first electrode sheet, and slotted cutouts from the uncoated conductive edges, the slotted cutouts angularly co-located relative to the cylindrical core upon forming the jellyroll structure.
H01M 10/0587 - Construction or manufacture of accumulators having only wound construction elements, i.e. wound positive electrodes, wound negative electrodes and wound separators
H01M 10/04 - Construction or manufacture in general
H01M 10/0525 - Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodesLithium-ion batteries
The invention relates to a novel solid state process for the preparation of metal-containing compounds comprising the steps i) forming a reaction mixture comprising one or more metal-containing precursor compounds and optionally one or more non-metal-containing reactants, and ii) using one or more hypophosphite-containing materials as a reducing agent; wherein one or more of the hypophosphite-containing materials is used as an agent to reduce one or more of the metal-containing precursor compounds; and further wherein the process is performed in the absence of an oxidizing atmosphere. Materials made by such a process are useful, for example, as electrode materials in alkali metal-ion battery applications.
H01B 1/06 - Conductors or conductive bodies characterised by the conductive materialsSelection of materials as conductors mainly consisting of other non-metallic substances
C01B 25/45 - Phosphates containing plural metal, or metal and ammonium
H01M 4/58 - Selection of substances as active materials, active masses, active liquids of inorganic compounds other than oxides or hydroxides, e.g. sulfides, selenides, tellurides, halogenides or LiCoFySelection of substances as active materials, active masses, active liquids of polyanionic structures, e.g. phosphates, silicates or borates
H01M 10/054 - Accumulators with insertion or intercalation of metals other than lithium, e.g. with magnesium or aluminium
H01M 4/136 - Electrodes based on inorganic compounds other than oxides or hydroxides, e.g. sulfides, selenides, tellurides, halogenides or LiCoFy
H01M 4/1397 - Processes of manufacture of electrodes based on inorganic compounds other than oxides or hydroxides, e.g. sulfides, selenides, tellurides, halogenides or LiCoFy
H01M 10/05 - Accumulators with non-aqueous electrolyte
The invention relates to a novel process for the preparation of metal-containing compounds comprising the steps of a) forming a mixture comprising i) elemental phosphorus and ii) one or more metal-containing precursor compounds, and b) heating the mixture to a temperature of at least 150° C. Materials made by such a process are useful, for example, as electrode materials in alkali metal-ion battery applications.
H01M 4/58 - Selection of substances as active materials, active masses, active liquids of inorganic compounds other than oxides or hydroxides, e.g. sulfides, selenides, tellurides, halogenides or LiCoFySelection of substances as active materials, active masses, active liquids of polyanionic structures, e.g. phosphates, silicates or borates
H01M 4/58 - Selection of substances as active materials, active masses, active liquids of inorganic compounds other than oxides or hydroxides, e.g. sulfides, selenides, tellurides, halogenides or LiCoFySelection of substances as active materials, active masses, active liquids of polyanionic structures, e.g. phosphates, silicates or borates
H01B 1/02 - Conductors or conductive bodies characterised by the conductive materialsSelection of materials as conductors mainly consisting of metals or alloys
Amorphous or partially amorphous nanoscale ion storage materials are provided. For example, lithium transition metal phosphate storage compounds are nanoscale and amorphous or partially amorphous in an as-prepared state, or become amorphous or partially amorphous upon electrochemical intercalation or de-intercalation by lithium. These nanoscale ion storage materials are useful for producing devices such as high energy and high power storage batteries.
4 precursor and the V—P—O/C precursor materials can be used interchangeably to produce the final vanadium phosphates, with the V—P—O/C precursor material being the preferred precursor. The precursors can subsequently be used to make vanadium based electroactive materials and use of such precursor materials offers significant advantages over other processes known for preparing vanadium phosphate compounds.
A compact, robust, multifunctional and highly manufacturable rechargeable battery cell is provided. The cell design dedicates minimal internal volume to inert components of the cell. This is accomplished, in part, by providing multiple functionalities to individual cell components.
4, where M is one or more transition metals. The nanoscale ion storage materials are useful for producing devices such as high energy and high power storage batteries, battery-capacitor hybrid devices, and high rate electrochromic devices.
H01M 4/58 - Selection of substances as active materials, active masses, active liquids of inorganic compounds other than oxides or hydroxides, e.g. sulfides, selenides, tellurides, halogenides or LiCoFySelection of substances as active materials, active masses, active liquids of polyanionic structures, e.g. phosphates, silicates or borates
An electrochemical cell is provided. The cell includes a plurality of electrode sheets separated by at least one separator sheet. A positive extension tab is attached to a current collecting tabs of positive electrode sheets, and a negative extension tab is attached to current collecting tabs of the negative electrode sheets. The dimensions of the positive extension tab and the negative extension tab are selected such that temperature difference between positive extension tab and the negative extension tab are minimized when the electrochemical cell is in use.
In some embodiments, a battery cell can include an assembly having an anode sheet and a cathode sheet separated by separator membranes, each sheet having an electroactive layer on a current collector. At least one of the current collectors can be in electrical communication with conducting tabs that extend from at least one of the anode sheet and the cathode sheet, the conducting tabs extends from an end face of the spirally wound assembly. In addition, the cell can include a first tab insulator having concentrically positioned outer and inner members, each of the outer and inner members having at least one slot that allows one or more of the plurality of conducting tabs to pass through. The inner and outer members are adjustable with respect to relative angular orientation of the at least one slot on the outer and inner members of the first tab insulator.
A cap assembly for use in an electrochemical cell. The cap assembly includes a tab collection post, a core insert, and at least one current collecting tab connected at one end to an electrode foil in the electrochemical cell, and horizontally connected at the other end to the tab collection post and the core insert. The at least one current collecting tab is disposed between and welded with the tab collection post and the core insert. The cap assembly also includes a shock absorber disposed around the core insert.
b) grinding said mixture in a jet mill for a period of time suitable to produce a generally homogeneous mixture of particles having a third average size smaller than said first average size. The precursor may be used as a starting material for making electrode active materials for use in a battery, comprising lithium, a transition metal, and phosphate or a similar anion.
H01M 4/58 - Selection of substances as active materials, active masses, active liquids of inorganic compounds other than oxides or hydroxides, e.g. sulfides, selenides, tellurides, halogenides or LiCoFySelection of substances as active materials, active masses, active liquids of polyanionic structures, e.g. phosphates, silicates or borates
C01B 25/45 - Phosphates containing plural metal, or metal and ammonium
26.
Amorphous and partially amorphous nanoscale ion storage materials
Amorphous or partially amorphous nanoscale ion storage materials are provided. For example, lithium transition metal phosphate storage compounds are nanoscale and amorphous or partially amorphous in an as-prepared state, or become amorphous or partially amorphous upon electrochemical intercalation or de-intercalation by lithium. These nanoscale ion storage materials are useful for producing devices such as high energy and high power storage batteries.
A compact, robust, multifunctional and highly manufacturable rechargeable cylindrical electrochemical cell is provided. In some embodiments, a cell can include a spirally wound assembly having an anode sheet and a cathode sheet separated by separator membranes, each sheet having a electroactive layer on a current collector. At least one of the current collectors can be in electrical communication with conducting tabs that extend from at least one of the anode sheet and the cathode sheet, the conducting tabs extends from an end face of the spirally wound assembly. The centers of the plurality of conducting tabs can be located within a 90 degree quadrant of an end face of the spirally wound assembly.
wherein A, X, a and b are selected to maintain the electroneutrality of the electrode active material in its nascent (as prepared or synthesized) state.
H01M 4/58 - Selection of substances as active materials, active masses, active liquids of inorganic compounds other than oxides or hydroxides, e.g. sulfides, selenides, tellurides, halogenides or LiCoFySelection of substances as active materials, active masses, active liquids of polyanionic structures, e.g. phosphates, silicates or borates
4, where M is one or more transition metals. The nanoscale ion storage materials are useful for producing devices such as high energy and high power storage batteries, battery-capacitor hybrid devices, and high rate electrochromic devices.
H01M 4/58 - Selection of substances as active materials, active masses, active liquids of inorganic compounds other than oxides or hydroxides, e.g. sulfides, selenides, tellurides, halogenides or LiCoFySelection of substances as active materials, active masses, active liquids of polyanionic structures, e.g. phosphates, silicates or borates
A compact, robust, multifunctional and highly manufacturable rechargeable battery cell is provided. The cell design dedicates minimal internal volume to inert components of the cell. This is accomplished, in part, by providing multiple functionalities to individual cell components.
4, where M is one or more transition metals. The nanoscale ion storage materials are useful for producing devices such as high energy and high power storage batteries, battery-capacitor hybrid devices, and high rate electrochromic devices.
H01M 4/58 - Selection of substances as active materials, active masses, active liquids of inorganic compounds other than oxides or hydroxides, e.g. sulfides, selenides, tellurides, halogenides or LiCoFySelection of substances as active materials, active masses, active liquids of polyanionic structures, e.g. phosphates, silicates or borates
H01B 1/08 - Conductors or conductive bodies characterised by the conductive materialsSelection of materials as conductors mainly consisting of other non-metallic substances oxides
H01M 4/58 - Selection of substances as active materials, active masses, active liquids of inorganic compounds other than oxides or hydroxides, e.g. sulfides, selenides, tellurides, halogenides or LiCoFySelection of substances as active materials, active masses, active liquids of polyanionic structures, e.g. phosphates, silicates or borates
33.
Low impedance layered battery apparatus and method for making the same
An electro-chemical storage device is described, and a method for making the same. In some aspects, a guidewire is co-wound with sheet or ribbon-like electrode materials so that contact is made between the guidewire and collector extensions of the electrode materials thereby forming an endcap with low impedance and high thermal sinking capabilities. In one embodiment, the storage device includes a negative electrode sheet have an edge which is substantially free of electrode active material, a positive electrode sheet have an edge which is substantially free of electrode active material, a first conductive guidewire disposed adjacent to the edge of the negative electrode sheet which is substantially free of electrode active material, and a second conductive guidewire disposed adjacent to the edge of the positive electrode sheet which is substantially free of electrode active material. The first conductive guidewire and the edge of the negative electrode sheet which is substantially free of electrode active material define a first electrode endcap and the second conductive guidewire and the edge of the positive electrode sheet which is substantially free of electrode active material define a second electrode endcap. The electrode endcaps are coupled to terminals of the storage device, which are capable of being connected to the terminals of an external circuit.
The present invention relates to a method for preparing an electroactive metal polyanion or a mixed metal polyanion comprising forming a slurry comprising a polymeric material, a solvent, a polyanion source or alkali metal polyanion source and at least one metal ion source; heating said slurry at a temperature and for a time sufficient to remove the solvent and form an essentially dried mixture; and heating said mixture at a temperature and for a time sufficient to produce an electroactive metal polyanion or electroactive mixed metal polyanion. In an alternative embodiment the present invention relates to a method for preparing a metal polyanion or a mixed metal polyanion which comprises mixing a polymeric material with a polyanion source or alternatively an alkali metal polyanion source and a source of at least one metal ion to produce a fine mixture and heating the mixture to a temperature higher than the melting point of the polymeric material, milling the resulting material and then heating the milled material. It is another object of the invention to provide electrochemically active materials produced by said methods. The electrochemically active materials so produced are useful in making electrodes and batteries.
3+, where M represents a metal in a +5 oxidation state. Reductive methods are provided for reacting a metal-oxo phosphate with an alkali metal compound in the presence of reducing carbon. The carbothermal reduction step can for example result in the reduction of a +5 metal to a +4 state or lower.
H01M 4/58 - Selection of substances as active materials, active masses, active liquids of inorganic compounds other than oxides or hydroxides, e.g. sulfides, selenides, tellurides, halogenides or LiCoFySelection of substances as active materials, active masses, active liquids of polyanionic structures, e.g. phosphates, silicates or borates
This invention relates to electrode active materials, electrodes, and batteries. In particular, this invention relates to active materials comprising lithium or other alkali metals, transition metals, +3 oxidation state non-transition elements, and phosphates or similar moieties.
H01M 4/58 - Selection of substances as active materials, active masses, active liquids of inorganic compounds other than oxides or hydroxides, e.g. sulfides, selenides, tellurides, halogenides or LiCoFySelection of substances as active materials, active masses, active liquids of polyanionic structures, e.g. phosphates, silicates or borates
H01M 4/52 - Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of nickel, cobalt or iron