Science 2015,350,530-533Rechargeable lithium-air(Li-O2)batteries have received considerable attentions due to their much higher theoretical energy densities than today’s lithium-ion batteries.However,they still suffer from at least four limitations:(1)much lower capacity than theoretical capacity,stemming from the small pore sizes and volumes of the current porous electrode;(2)side reactions,including electrode materials,electrolyte,intermediate and final discharge products;(3)large hysteresis