Two-dimensionally porous cobalt sulfide nanosheets as a high-performance cathode for aluminum-ion batteries

Rechargeable aluminum-ion batteries (AIBs) are regarded as a great potential developing energy storage device with the advantages of abundant resources, high theoretical specific capacity and high safety. Nevertheless, the scarcity of suitable cathode materials with satisfactory rate performance and cycling stability hinders its further development and wider field of application. Here, we demonstrate a strategy for designing a novel two-dimensionally porous Co9S8 nanosheets as the cathode materials for AIBs. The electrode exhibits an outstanding electrochemical performance with an excellent cycling stability (maintains 120 mAh g(-1) after 250 cycles at 0.2 A g(-1)) and enchanted rate performance (60 mAh g(-1) at 2 A g(-1) and can quickly recover to 120 mAh g(-1) when the current density is reduced back to 0.1 A g(-1)). Furthermore, high capacity retentions and superior stability for the assembled soft-pack batteries can also be achieved under high and low temperatures and stringent bending conditions. The remarkable aluminum storage behavior of the engineered Co9S8 cathode is attributed to its unique two dimensional (2D) geometrical architecture, abundant internal porosity and nanosized secondary building blocks. Our findings appear to provide a potential new avenue in the design of cathode materials in AIBs. [GRAPHICS] .