High-Efficiency Electrolyte for Li-Rich Cathode Materials Achieving Enhanced Cycle Stability and Suppressed Voltage Fading Capable of Practical Applications on a Li-Ion Battery.

Abstract

Li-rich cathodes have been in considerable attention for their high reversible capacity. However, they have serious problems like poor cycling with intense capacity decay and voltage fading, which restrict their access to practical applications. In this work, a facile and efficient strategy is proposed to alleviate these intrinsic issues with a high-efficiency electrolyte system. This special electrolyte enables Li-rich cathodes to deliver superior integrated performance with a high initial discharge capacity of 301 mAh·g-1, outstanding cycling stability with a capacity retention of 88% at 0.5 C over 500 cycles, and a remarkable rate capability of 136 mAh·g-1 at 5 C, respectively. What is more, the voltage fading is largely suppressed. Physical and electrochemical characterizations demonstrate that the robust CEI film formed on the cathode surface contributes to the improved electrochemical performance. This work provides a new approach to surmount defects of Li-rich materials and will largely promote their practical applications on Li-ion batteries.