Jiang Yu, Yang Yang, Xu Rui, Cheng Xiaolong, Huang Huijuan, Shi Pengcheng, Yao Yu, Yang Hai, Li Dongjun, Zhou Xuefeng, Chen Qianwang, Feng Yuezhan, Rui Xianhong, Yu Yan
Hefei National Laboratory for Physical Sciences at the Microscale, Department of Materials Science and Engineering, CAS Key Laboratory of Materials for Energy Conversion, University of Science and Technology of China, Hefei, Anhui 230026, China.
School of Materials and Energy, Guangdong University of Technology, Guangzhou, Guangdong 510006, China.
ACS Nano. 2021 Jun 22;15(6):10217-10227. doi: 10.1021/acsnano.1c02275. Epub 2021 May 26.
Carbonaceous materials have been considered as promising anodes for potassium-ion batteries (PIBs) because of their high electronic conductivity, eco-friendliness, and structural stability. However, the small interlayer spacing and serious volume expansion caused by the repeated insertion/extraction of large K-ions restrict their potassium-ion storage performance. Herein, F and N codoped carbon nanosheets (FNCS) with rich-edge defects are designed to resolve these problems. The F doping is in favor of the formation of more edge defects in the carbon layer, offering strong K adsorption capability and promoting the K storage. The ultrathin carbon nanosheets can provide a large contact area for the electrochemical reactions and shorten the transportation pathways for both K-ions and electrons. Consequently, the FNCS anode shows a high reversible capacity (610 mAh g at 0.1 A g) and ultrastable cyclability over 4000 cycles at 5 A g. Moreover, K-ion full cells (FNCS|KFeFe(CN)) display excellent cycling stability (128 mAh g at 1 A g after 500 cycles) and rate capability (93 mAh g at 20 A g). This design strategy can be extended to design other electrode materials for high-performance energy storage, such as magnesium-ion batteries, supercapacitors, and electrocatalysis.
碳质材料因其高电子导电性、环境友好性和结构稳定性，被认为是钾离子电池（PIB）有前景的阳极材料。然而，大尺寸钾离子的反复嵌入/脱出导致的层间距小和严重的体积膨胀限制了它们的钾离子存储性能。在此，设计了具有丰富边缘缺陷的氟和氮共掺杂碳纳米片（FNCS）来解决这些问题。氟掺杂有利于在碳层中形成更多的边缘缺陷，提供强大的钾吸附能力并促进钾存储。超薄碳纳米片可为电化学反应提供大的接触面积，并缩短钾离子和电子的传输路径。因此，FNCS阳极在0.1 A g时显示出高可逆容量（610 mAh g），在5 A g下经过4000次循环具有超稳定的循环性能。此外，钾离子全电池（FNCS|KFeFe(CN)）表现出优异的循环稳定性（500次循环后在1 A g时为128 mAh g）和倍率性能（在20 A g时为93 mAh g）。这种设计策略可扩展到设计用于高性能能量存储的其他电极材料，如镁离子电池、超级电容器和电催化。
