Constructing Robust Cathode/Electrolyte Interphase for Ultrastable 4.6 V LiCoO2 under -25 °C.

Abstract

Improving the durability of cathode materials at low temperature is of great importance for the development nowadays of lithium ion batteries, since the practical capacity and cycling stability of the electrode are reduced significantly at low temperature. Herein, by amorphous Zr3(PO4)4 surface engineering, we realize a stable high-voltage LiCoO2 operation (4.6 V) at -25 °C. The highly amorphous surface layer can help to form a high-quality cathode-electrolyte interphase with strong stability and low interface resistance, especially at low temperature. Such a surface-engineered LiCoO2 shows a capacity of 179.2 mAh g-1 at 0.2C and an excellent cyclability with 91% capacity retention after 300 cycles (1C). As a comparison, bare LiCoO2 shows only 161.6 mAh g-1 and 1% capacity retention under the same circumstances. This work confirms that surface regulation and control engineering is an effective route to improve the high-voltage and low-temperature performance of LiCoO2.