In situ gelatin carbonation to prepare a binder-free LiFePO4 cathode for high-power lithium ion batteries

A binder-free LiFePO4 cathode is prepared by simple in situ gelatin carbonation at 600 °C under pure N2. In this process, gelatin which is used as a binder in the traditional electrodes, is converted into carbon materials evenly and coated on LiFePO4 with acetylene black particles. The obtained binder-free cathode possesses uniform distribution of LiFePO4 and acetylene black, gelatin-based carbon coating and the porous structure. The gelatin-based carbon coating can enhance the effective electronic conductivity among LiFePO4, acetylene black particles and current collector. And the porous structure formed by decomposition and shrinkage during carbonation of gelatin can facilitate penetration of the liquid electrolyte into the pores, serving as a fast ionic pathway. The electrochemical results show the rate capability is greatly improved and the discharge capacity still reaches 108 mAh/g at 5 C. There is almost no capacity fading at the same C-rate cycles.