A dual pore carbon aerogel based air cathode for a highly rechargeable lithium-air battery

•Carbon aerogel's dual-pore enables mass transport in two separate channels.•Low carbon loading cathode is favorable for lithium-air batteries' reversibility.•A current density between 0.10 and 0.20 mA cm−2 contributes to better cyclability.

Cathode structure plays a vital role in lithium-air battery for that it can provide space for discharged products accommodation and free path for oxygen, e− and Li+ transport. However, pore blockage, cathode passivation and degradation all result in low discharge rates and poor cycling capability. To get rid of these predicaments, a novel highly conductive dual pore carbon aerogel based air cathode is fabricated to construct a lithium-air battery, which exhibits 18 to 525 cycles in the LiTFSI/sulfolane electrolyte at a current density varying from 1.00 mA cm−2 to 0.05 mA cm−2, accompanied by a high energy efficiency of 78.32%. We postulate that the essence lies in that the as-prepared air cathode inventively create a suitable tri-phase boundary reaction zone, facilitating oxygen and Li+ diffusion in two independant pore channels, thus realizing a relative higher discharge rate capability, lower pore blockage and cathode passivation. Further, pore structure, carbon loading, rate capability, discharge depth and the air's effect are exploited and coordinated, targeting for a high power and reversible lithium-air battery. Such nano-porous carbon aerogel air cathode of novel dual pore structure and material design is expected to be an attractive alternative for lithium-air batteries and other lithium based batteries.

Graphical abstractA highly conductive dual pore carbon aerogel air cathode is successfully synthesized, favorable for the fast mass transport and superior discharged products accommodation/decomposition, thus realizing a relatively high discharge rate cycling performance and impaired cathode passivation. This work targets for exploiting a high power and reversible lithium-air battery by coordinating the necessary ingredients: carbon loading and current density et al.Figure optionsDownload full-size imageDownload as PowerPoint slide