Research of Dual-Ion Polymer Batteries Based on N-butyl-N-methylpiperidinium Bis(trifluoromethylsulfonyl)imide Ionic Liquid Electrolyte

The development of dual-ion metal-free batteries is restricted by the strong self-discharge effect and dissolution of some anode active materials in the polar electrolyte. This in turn leads to low coulombic efficiency and discharge capacity loss. It is of great significance to alleviate this phenomenon through the redox reactions of polymeric active materials. In this study, a metal-free poly(anthraquinonyl sulfide)-graphite battery was constructed based on a pure N-butyl-N-methylpiperidinium bis(trifluoromethylsulfonyl)imide ionic liquid electrolyte. The cell had a discharge capacity of 70.5 mAh g−1 (0.1 C) and a capacity retention rate of 98.6% after 100 cycles, with a coulombic efficiency of 98.3% (1 C). Comparative studies proved that the self-discharge effect of poly(anthraquinonyl sulfide)-graphite batteries is weaker than that of some dual-graphite batteries. Cyclic voltammetry experiments revealed that the redox reaction was highly reversible. Most significantly, this type of poly(anthraquinonyl sulfide)-graphite batteries provides a new way for the design of metal-free dual-ion batteries with excellent long-term cycling performance and minimal self-discharge effect.