Fig. 24.

a Schematic illustration for the reaction process during cycling. Reproduced with permission from Ref. [63]. b Schematic diagram of the synergistic effect of N-doped carbon layer and W₂C nanoparticles as Li-O₂ battery catalyst. Reproduced with permission from Ref. [142]. c Comparison of the cycling performances of graphene and G@CN free-standing macroporous electrode. Reproduced with permission from Ref. [143]. d Cycle performance of RuO₂@m-BCN in Li-O₂ batteries with a current density of 0.3 mA cm⁻². Reproduced with permission from Ref. [144]. e First discharge curves of Co₃O₄ and Ag/g-C₃N₄/Co₃O₄ as catalysts at a current density of 100 mA g⁻¹ f First charge/discharge curves of the Ag/g-C₃N₄/Co₃O₄ as a catalyst at a current density of 500 mA g⁻¹. Reproduced with permission from Ref. [145]. Copyright permissions from Springer Nature, Elsevier, Wiley–VCH, and Royal Society of Chemistry. (Color figure online)