Ultralong cycle life and high rate potassium ion batteries enabled by multi-level porous carbon

Carbon materials are widely exploited in anode materials for potassium ion batteries (PIBs) due to low cost and non-toxicity. Herein, multi-level porous carbon (MLPC) for PIBs is obtained by facile synthesis method. According to analysis results, the MLPC with three dimensional (3D) interconnected networks possesses high specific surface area (671.56 m(2) g(-1)), enhancing the electronic, as well as ionic transfer. Meanwhile, the multi-level pores pertaining to micropores on the surface of nanofibers, micropores and mesopores between nanofibers and nanofibers, and macropores originating from the interlinked networks, are observed in the MLPC. The micro and mesopomus structures facilitate K-ion adsorption/desorption, and promote capacitive-controlled contributions, which improves the electrochemical reaction kinetics of the PIBs. Additionally, the macropores providing shorter K-ion transportation pathways further promote the K-ion diffusion. Given aforementioned unique structural features, the depotassiation capacity of 136.9 mAh g(-1) is remained at 5.0 A g(-1) over 9600 cycles. Moreover, remarkable reversible capacity of 260.1 mAh g(-1) is achieved at a high charge/discharge rate of 2.0 A g(-1). These results confirm the MLPC is a promising anode material for the PIBs with stable cycling, fast charge, and long lifespan.

Automated summary

Multi-level porous carbon (MLPC) with high specific surface area, multi-level pore structure, and macropores facilitates electronic and ionic transfer for potassium ion batteries (PIB), promoting capacitive contributions and K-ion diffusion, resulting in improved electrochemical performance.