Porous FeF 3 /MWCNTs composite cathode promoting high performance aluminum storage.

Rechargeable aluminum-ion batteries (RAIBs) attract great attention for stationary energy storage, but there remains a lack of suitable cathode materials for them. Here, a porous iron fluoride/multi wall carbon nanotube (FeF 3 /MWCNTs) composite as a cathode for RAIBs shows high discharge capacity (180 mA h g -1 ) and good rate performance, while MWCNTs play crucial roles in improving conductivity and cycle stability. Various characterizations elucidate its conversion-type mechanism, in particular, the Fe 3+ /Fe 2+ conversion exhibits a high operating potential of 1.75 V and discharge capacity of 123 mA h g -1 , which is very promising for practical applications.