High Oxidation Potential ≈6.0 V of Concentrated Electrolyte toward High-Performance Dual-Ion Battery

Dual-ion batteries (DIBs) show the advantages of high working voltage, cost-effectiveness, and environmental friendliness, but conventional electrolytes commonly cannot satisfy simultaneously the requirements of wide voltage range and high-concentration, leading to poor cycling durability and limited energy density. In this work, an electrolyte system with 4.0 m lithium bis(fluorosulfonyl)imide (LiFSI) dissolved in tetramethylene sulfone, which shows merits of i) high oxidation potential approximate to 6.0 V to enable the insertion/deinsertion of FSI- reversibly at the graphite cathode, ii) dramatically suppressed gas formation under high working voltage, and iii) significantly elevated full-cell DIB energy density, is developed. The DIB constructed with such an electrolyte is able to exhibit 113.3 mAh g(-1) capacity and approximate to 4.6 V medium discharge voltage at 200 mA g(-1), along with 94.7% capacity retention after 1000 cycles. Moreover, this DIB delivers an energy density of approximate to 180 Wh kg(-1) (including electrolyte which contributes to the capacity and electrode materials), one of the best performances amongst the related work on DIBs.

Automated summary

A novel electrolyte system has been developed to enhance the performance of dual-ion batteries, improving capacity, suppressing gas formation, and increasing energy density.