Li4Ti5O12-Hard carbon composite anode for fast-charging Li-Ion batteries

The fast charge of lithium-ion batteries (LIBs) needs anode and cathode materials operating at high current densities and thus require special consideration for the electrode materials. This work studies the effect of the loading ratio of Hard Carbon (HC) and Li4Ti5O12 (LTO) on the electrochemical behavior of fast-charging LIBs. The formation of LTO/HC composites is confirmed with structural characterizations and electronic con-ductivity measurement. Galvanostatic charge-discharge cycling testing shows that superior cycling stability and specific capacity are achieved for the LTO/HC composite electrode with 20 wt% HC (LTO-HC20). Electrochemical impedance spectroscopy study reveals the improved lithium diffusion coefficient of LTO-HC compared to LTO only. Post-mortem analysis suggests that the LTO-HC composite electrodes, with an opti-mized LTO to HC ratio, can effectively contribute to improved Li-ion storage and electronic conductivity and robust solid electrolyte interphase on the electrode surface. Finally, full cells consisting of the optimized anode (LTO-HC20) and cathode (NMC 333) are fabricated and evaluated. It is found that a full cell of NCM/LTO-HC20 exhibits capacity retention of 82% and 79% over 300 cycles and specific energy of 130 and 89 Wh kg-1 at 1C and 3C, respectively. Therefore, a specific ratio of HC in the LTO-HC composite anode can dramatically improve the battery performance and specific energy while reducing the cost.