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.

A 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 as PowerPoint slide