Nitrogen-doped carbon derived from pre-oxidized pitch for surface dominated potassium-ion storage

Graphitic material has captured tremendous attentions as anode material for potassium ion batteries (PIBs). Nevertheless, the large radius of potassium-ions results in sluggish potassiation kinetics and huge volume expansion, leading to unsatisfying performance. Herein, a fabrication facile, cost-effective and high carbon yield nitrogen/oxygen co-doped amorphous carbon (NOC) with pitch and urea as precursors is reported. Pre-oxidation process is employed, maintaining the amorphous structure of pitch derived carbon against its soft carbon nature. The NOC electrode delivers reversible capacities of 347 (300th cycle) and 167 mAh g(-1) (1000th cycle) at 100 and 2000 mA g(-1), respectively. Rearrangement of graphene layers in short range benefits the structure stability against volume change. Kinetics analyses prove that surface-induced capacitive process dominates in K-ion storage mechanism, which contributes to the remarkable electrochemical performance. Pouch full cells were assembled, delivering a capacity of 316 mAh g(-1) at 100 mA g(-1). In view of the cost-effectiveness and electrochemical performance, this work offers a strategy for the fabrication of low-cost and high-performance PIB anode materials. (C) 2019 Elsevier Ltd. All rights reserved.