Constructing Highly Li+ Conductive Electrode Electrolyte Interphases for 4.6 V Li||LiCoO2 Batteries via Electrolyte Additive Engineering

To improve voltage is considered to effectively address the energy-density question of Li||LiCoO2 batteries. However, it is restricted by the instability of electrode electrolyte interphases in carbonate electrolytes, which mainly originates from Li dendrite growth and structural instability of LiCoO2 at high voltage. Herein, an electrolyte additive strategy is proposed for constructing efficient LiNxOy-contained cathode electrolyte interphase for 4.6 V LiCoO2 and LiF-rich solid electrolyte interphase for Li anode to enhance the stability of Li||LiCoO2 battery using 4-nitrophthalic anhydride as the additive. As expected, the Li||LiCoO2 battery can stably operate up to 4.6 V, with a high specific capacity of 216.9 mAh g(-1) during the 1st cycle and a capacity retention of 167.1 mAh g(-1) after 200 cycles at 0.3 C. This work provides an available strategy to realize the application of high-voltage Li||LiCoO2 battery.

Automated summary

An electrolyte additive strategy is proposed to improve the stability and voltage of Li||LiCoO2 batteries, by constructing efficient LiNxOy-contained cathode electrolyte interphase and LiF-rich solid electrolyte interphase. The Li||LiCoO2 battery can operate stably up to 4.6 V, with high specific capacity and capacity retention.