Nanoscale ion storage materials
AssigneeA123 Systems, Inc.
InventorsYet-Ming Chiang, Antoni Gozdz, Martin Payne
Life of this patent
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Abstract
Nanoscale ion storage materials are provided that exhibit unique properties measurably distinct from their larger scale counterparts. For example, the nanoscale materials can exhibit increased electronic conductivity, improved electromechanical stability, increased rate of intercalation, and/or an extended range of solid solution. Useful nanoscale materials include alkaline transition metal phosphates, such as LiMPO4, 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.
Claims62
A lithium transition metal phosphate powder having a specific surface area of at least 15 m2/g and having a lithium content at room temperature (23° C.) that is least 2 mole % less than the lithium content of a lithium transition metal phosphate of the same composition prepared in a bulk form or as a powder of specific surface area less than about 10 m2/g.
A lithium iron phosphate composition forming a single crystalline phase of the olivine structure at room temperature and having a solid solution composition Li1-xFePO4, wherein x is greater than 0.01.
A partially lithiated iron phosphate composition of the olivine structure having at room temperature a single crystalline phase of the olivine structure and a solid solution composition LiyFePO4 wherein y is greater than 0.01.
A lithium transition metal phosphate compound characterized in that, when used as a lithium storage electrode in a standard electrochemical cell wherein the counterelectrode is lithium metal, the compound exhibits a continuously decreasing charging current upon charging in a potentiostatic intermittent titration (PITT) procedure at a constant overpotential of 50 mV above the open-circuit voltage of the cell, said open-circuit voltage being measured after charging to a 50% state of charge and holding for at least 12 hours.
A lithium transition metal phosphate compound characterized in that, when used as a lithium storage electrode in a standard electrochemical cell wherein the counterelectrode is lithium metal, the compound exhibits a continuously decreasing charging current upon discharging in a potentiostatic intermittent titration (PITT) procedure at a constant overpotential of 50 mV above the open-circuit voltage of the cell, said open-circuit voltage being measured after charging to a 50% state of charge and holding for at least 12 hours.
Dependencies are inferred from the claim text.