A Safer High-Energy Lithium-Ion Capacitor Using Fast-Charging and Stable omega-Li3V2O5 Anode

Lithium-ion capacitors (LICs) are flourishing toward high energy density and high safety, which depend significantly on the performance of the intercalation-type anodes used in LICs. However, commercially available graphite and Li4Ti5O12 anodes in LICs suffer from inferior electrochemical performance and safety risks due to limited rate capability, energy density, thermal decomposition, and gassing issues. Here a safer high-energy LIC based on a fast-charging omega-Li3V2O5 (omega-LVO) anode with a stable bulk/interface structure is reported. The electrochemical performance, thermal safety, and gassing behavior of the omega-LVO-based LIC device are investigated, followed by the exploration of the stability of the omega-LVO anode. The omega-LVO anode exhibits fast lithium-ion transport kinetics at room/elevated temperatures. Paired with an active carbon (AC) cathode, the AC||omega-LVO LIC with high energy density and long-term endurability is achieved. The accelerating rate calorimetry, in situ gas assessment, and ultrasonic scanning imaging technologies further verify the high safety of the as-fabricated LIC device. Theoretical and experimental results unveil that the high safety originates from the high structure/interface stability of the omega-LVO anode. This work provides important insights into electrochemical/thermochemical behaviors of omega-LVO-based anodes within LICs and offers new opportunities to develop safer high-energy LIC devices.