“…[353][354][355] For example, Li-O 2 and Al-air batteries possess high theoretical energy densities of 11140 Wh kg -1 and 8135 Wh kg -1 , respectively, which are thirty and twenty times higher than LIBs. 353 In a typical example, Co 9 S 8 nanoparticles embedded graphitic layers decorating on N,S dual-doped porous CNFs (Co 9 S 8 @G/NS-PCNFs) have been prepared as a free-standing bifunctional electrodes for both Li-O 2 and Al-air batteries. 353 In this hybrid system, the N,S dual-doped porous CNFs offer abundant active sites, enabling excellent electron and mass transport as well as electrolyte immersion.…”