Defining role of the surface and bulk contributions in camphoric carbon grafted lithium nickel manganese oxide powders for lithium ion batteries

In the present study, lithium nickel manganese oxide powders grafted with camphoric nano-carbons have been exploited to fabricate high voltage, high capacity rechargeable electrodes for Li storage. The prepared lithium nickel manganese oxide particles were pyrolyzed using a camphoric solution to graft porous camphoric carbon layer on to the surface. A detailed study was performed to elucidate the effect of carbon content on the performance of the electrode. Relative contributions of capacitive and diffusion-controlled processes underlying these composite electrodes have been mathematically modeled. The lithium nickel manganese oxide composites showed two times higher conductivity as compared to the pristine samples. These electrodes exhibited a specific capacity value of ~154 mAhg-1 and showed good rate capability. The capacity fading was found to be ~17% at the end of 200 cycles for 100% depth of discharge. The specific capacity and capacity retention for these blends were found to be ~10% and ~40% higher respectively than pristine powders which are promising considering their low cost and facile fabrication process.