Room temperature solid state dual-ion batteries based on gel electrolytes

The volume expansion of the electrodes and gas generation are still challenges for the current dual-ion batteries. Herein, we report a novel room temperature solid state dual-ion battery based on gel electrolytes. The dual-ion battery delivers a high reversible capacity of ∼80 mA h g−1, with excellent rate performance and long-term cycling stability. Moreover, the battery displays a high working voltage of 4.2 V, which enables to improve the application value of the battery. Typically, the problem of gas generation is further reduced by altering the charge cut-off voltage with gel electrolytes. First-principles simulations are performed to elucidate the anion intercalation behavior in a graphite cathode, demonstrating that the anion-intercalated graphite is stable without obvious distortion, and small activation energy barriers and fast ion-diffusivity are also reported. These convincing results indicate that this dual-ion battery is promising and environmentally friendly for future energy storage applications.