Negative electrode for lithium batteries

Abstract

An active material for high-voltage negative electrodes (>1V vs. Li) of secondary rechargeable lithium batteries is disclosed. Chemical composition is represented by the general formula Li2+vTi3−WFeXMyM′ZO7−α, where M and M′ are metal ions having an ionic radius between 0.5 and 0.8 A and forming an octahedral structure with oxygen, like Ti3+, Co2+, Co3+, Ni2+, Ni3+, Cu2+, Mg2+, Al3+, In3+, Sn4+, Sb3+, Sb5+, α is related to the formal oxidation numbers n and n′ of M and M′ by the relation 2α=v+4w−3x−ny−n′z and the ranges of values are −0.5≦̸V≦̸0.5, 0≦̸w≦̸0.2, x>0, y+z>0 and x+y+z≦̸0.7. The structure is related to that of ramsdellite for all the compositions. The negative active material is prepared by ceramics process wherein lithium oxide, titanium oxide, iron oxide, M and / or M′ oxide are used as starting material for synthesis. Inorganic or organic solid precursors of the oxides can also be used instead. After reactant dispersion the mixture is fired. The resulting electrochemically active material provides low working voltage and capacity with excellent cycling capabilities at both low and high current densities.

Description

technical field [0001] The present invention relates to rechargeable lithium batteries. More specifically, the present invention relates to an active material for a negative electrode of a secondary rechargeable battery, wherein the active material is based on lithium titanoramite oxide having one or both of the following elements: Ti 3+ ,Co 2+ ,Co 3+ , Ni 2+ , Ni 3+ , Cu 2+ , Mg 2+ , Al 3+ , In 3+ , Sn 4+ , Sb 3+ , Sb 5+ . Improved performance, high energy, and high power factor for safety and the environment at reasonable cost. Background technique [0002] Anode materials for rechargeable lithium batteries are usually selected from the carbon family. In these batteries, considerable efforts have been made to find alternative materials for electrochemically active anodes to replace graphite. Notably, due to the average voltage of about 1.5 V relative to Li, lithium titanium oxides such as the spinel phase Li mentioned in Journal of Electrochemical Society 141...

AI Technical Summary

Problems solved by technology

However, due to Fe 3+ / Fe 2+ conversion, the first discharge curve shows a plateau, which limits the reversible capacity, and with Li 2 Ti 3 o 7 Compared with the other performance

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