Improved rate capability of highly loaded carbon fiber-interwoven LiNi0.6Co0.2Mn0.2O2 cathode material for high-power Li-ion batteries

High loading level of micron cathode active material is essential for high energy density Li-ion batteries. High loading level and thick cathode however limit not only rate capability but also cycle life, which is mainly caused by inhomogeneous current distribution from bottom (current collector side) to the top ( interface side to electrolyte) of the cathode. Here we report a significant improvement of rate performance of micron LiNi0.6Co0.2Mn0.2O2 cathode material with high loading level of more than 10 mgcm(-2), through simple and homogeneous dispersion and interweaving of bulk carbon fibers (CF) to active material. This microstructure permits the building-up of 3D electrical conduction network over the thick cathode. While the interwoven carbon fiber network guarantees fast electron transfer, porous characteristic of a thick cathode leads to a rapid access of Li+-ion through a good electrolyte wetting, and favorable rate capability and cycling stability. The resulting highly loaded CF-interwoven cathode achieves rate capability upto 5 C, high capacity of 163 mAhg(-1) at 1 C and stable 1 C cycling performance even under an aggressive test condition between 3.0 and 4.6 V utilizing high-voltage electrolyte additive. (C) 2015 Elsevier B.V. All rights reserved.