Tuning hierarchical structure of probiotics-derived porous carbon for potassium-ion batteries

Biomass derived carbon-based materials are considered as prospective anode candidates for potassium ion batteries (PIBs) because of their abundant resources, low cost, high specific surface area and abundant active sites. However, the practical application of carbon-based electrodes for PIBs is intrinsically hindered by the unsatisfactory reversible capacity caused by the huge volume expansion during the embedding of potassium ions. Herein, a three-dimensional (3D) probiotics-derived porous N doped carbon nanosheets aggregate with the highly branched car-bon nanotube (denoted as 3D-PNC@CNTs) is designed as advanced anode for PIBs. The as-prepared 3D-PNC@CNTs possesses the 3D interconnected conductive framework composed of ultrathin carbon nanosheets, rich hierarchical pores, and high edge defects. These features facilitate the rapid electrons/ions transfer, provide enough space to accommodate the huge volume change, ensure easy electrolyte infiltration and provide many active sites for K+ storage. By virtue of these features, 3D-PNC@CNTs displays a high reversible capacity of 458 mAh g- 1 at 100 mA g-1 and excellent cycling stability (143 mAh g-1 at 1000 mA g-1 after 500 cycles). This work provides important insights into biomass materials as promising anode materials for rechargeable PIBs.