Quasi-Solid-State Li–O₂ Batteries with Laser-Induced Graphene Cathode Catalysts

Li–O2 batteries are attracting considerable interest due to their outstanding theoretical capacities and energy densities. The liquid electrolyte and insulating nature of discharge products hinder further development. We present a practical strategy for durable Li–O2 batteries with high cyclable capacity up to 2 mAh/cm2. A dual polymer gel electrolyte (DPGE) networking strategy is proposed for the quasi-solid electrolyte. Lowering the use of liquid components in the electrolyte would suppress the possible side reaction with superoxide intermediates. The DPGE is further combined with a highly effective Mn-based catalyst that is prepared by direct laser writing on polymers to produce the quasi-solid-state Li–O2 batteries. The DPGE sustains a highly reversible Li plating/stripping process without short-circuiting or an increase in interfacial resistance for over 2000 h. Furthermore, the Li–O2 battery demonstrated stable galvanostatic charge/discharge performance for over 200 cycles (2000 h) with a cutoff capacity of 0.4 mAh/cm2. The battery delivers a high reversible capacity of 2.0 mAh/cm2 at an elevated current density of 0.4 mA/cm2, while the charging potential is maintained at a low value. Studies were performed during discharge and charge process to investigate the underlying mechanism. This work could contribute to a better practical design of Li–O2 batteries.