(503a) High Capacity Lithium Rich Metal Oxide Cathodes with Single Wall Carbon Nanotube Conductive Additives for Lithium Ion Batteries

The recent development of high capacity (>250 mAh/g) lithium rich metal oxide cathodes, Li₂MnO₃•LiNi_xMn_yCo_zO₂, are promising materials to increase the energy density of lithium ion batteries.  However, limitations still exist in the rate capability of the material and few studies have thoroughly investigated the thermal stability and safety of these novel cathodes.  Recently, the use of single wall carbon nanotubes (SWCNTs), at a low weight percent (1% w/w) as a conductive additive in a LiNiCoO₂ cathode composite, has been shown to improve the electrochemical performance and safety of the cathode composite compared to traditional carbon black conductive additives.  The capacity retention of the composite with SWCNTs at a 10C rate was three times greater than the composite with carbon black additives. The thermal stability of the electrode was improved as well with a 40% decrease in the exothermic energy released from an overcharged cathode composite containing SWCNTs as measured by differential scanning calorimetry (DSC).  The use of SWCNT additives is extended to lithium rich metal oxide cathode composites where the weight percentage of SWCNT additives is varied and compared to composites with carbon black additives to optimize the energy density and rate capability of this novel cathode composite.  The effect of cathode material loading and composite thickness will be related to the thermal stability to determine the safety with varying SWCNT additive concentration.