Electrodes having composite xLi2M’O3·(1-x)LiMO2 structures in which an electrochemically inactive Li2M’O3 component is integrated with an electrochemically active LiMO2 component to provide improved structural and electrochemical stability. The preferred M’ ions are manganese, titanium and zirconium, whereas the preferred M ions are manganese and nickel, which can be used in combination with other metals such as cobalt. For example, the composite electrode 0.10Li2MnO3·0.90LiMn0.26Ni0.37Co0.37O2, which can also be represented in conventional layered notation as Li[Li0.0475Mn0.3175Ni0.3175Co0.3175]O2, shows outstanding electrochemical properties. The structural compatibility between the two components, both of which have layered configurations (Fig. 1), allows integration to occur at the atomic level.
During charge and discharge of a lithium-ion cell, Li+ ions are electrochemically removed from and reinserted into the LiMO2 component, respectively, as shown schematically in a compositional phase diagram of a Li2M’O3 - LiMO2 - MO2 - Li2MO2 electrode system (Fig. 2). An additional advantage of using electrode structures with manganese and nickel ions in the LiMO2 component is that these structures can accommodate additional lithium; they form layered Li2MO2 structures without compromising the reversibility of the reaction, thereby providing additional capacity to the electrode. The Li2M’O3 component not only provides structural stability but also ensures, with its high lithium content, that the lithium layers in the composite electrodes are not contaminated by small amounts of transition metal ions, such as Ni2+ ions.
- Superior cost and safety features over state-of-the-art LiCoO2 electrodes
- Can be charged and discharged at high rates
Applications and Industries
Electrodes used in batteries for
- Electric and plug-in hybrid electric vehicles;
- Portable electronic devices;
- Medical devices; and
- Space, aeronautical, and defense-related devices.
Ready for commercialization