Tannic acid mediated coating of Al-Ti-oxide nanolayer on LiCoO2 cathode for high-voltage lithium-ion batteries

High-voltage LiCoO2 (LCO) satisfies the demand of high-energy lithium-ion batteries, but suffers adverse factors including structural irreversibility, micro-crack formation, active material erosion and electrode/electrolyte side reactions, which limits its electrochemical performance beyond 4.2 V. Here, we employed a surface coating method based on tannic acid (TA) pretreatment to vary the properties of LCO surface. The TA-mediated Al-Ti oxide (ATO) coating on LCO resulted in the interface doping of Al3+ and Ti4+ as well as the spinel phase transition layer, which inhibited the surface degradation and the structural instability. As a result, the obtained [email protected]% maintained 112 mAh g−1 after 600 cycles with a high voltage of 4.5 V. It also exhibited capacity retention of 80% after 100 cycles at 45 °C and the rate performance of 155 mAh g−1 at 10 C.