Biowaste Orange Peel-Derived Mesoporous Carbon as a Cost-Effective Anode Material with Ultra-Stable Cyclability for Potassium-Ion Batteries

Potassium-ion batteries (PIBs) are promising alternative to Lithium-ion batteries (LIBs) owing to their economic merits. However, the PIBs have not met suitable anode materials comparable to graphite in LIBs. We synthesised an orange peel-derived mesoporous carbon (OPDMC) as a potential anode material for high performance PIBs via facile one-step carbonisation with self-activation from waste orange peel. The OPDMC-1000, which were carbonised at 1000 degrees C, exhibited impressive initial discharge/charge capacities of 408/224 mAh g(-1)at 30 mA g(-1)and retained the reversible capacity of 208.57 mAh g(-1)over 100 cycles. Even after 2000 and 3000 cycles at specific currents of 200 and 500 mA g(-1), it maintained the reversible capacities of 150.37 and 112 mAh g(-1), respectively. A full cell employing the OPDMC exhibited an initial reversible discharge capacity of 185.32 mAh g(-1)at 50 mA g(-1)with capacity retention of 71.60 % after 50 cycles, indicating its practical applicability.