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Ultrafast Potassium Storage in F‑Induced Ultra-High Edge-Defective Carbon Nanosheets

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journal contribution
posted on 2021-05-26, 18:25 authored by Yu Jiang, Yang Yang, Rui Xu, Xiaolong Cheng, Huijuan Huang, Pengcheng Shi, Yu Yao, Hai Yang, Dongjun Li, Xuefeng Zhou, Qianwang Chen, Yuezhan Feng, Xianhong Rui, Yan Yu
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–1 at 0.1 A g–1) and ultrastable cyclability over 4000 cycles at 5 A g–1. Moreover, K-ion full cells (FNCS|K2FeFe­(CN)6) display excellent cycling stability (128 mAh g–1 at 1 A g–1 after 500 cycles) and rate capability (93 mAh g–1 at 20 A g–1). This design strategy can be extended to design other electrode materials for high-performance energy storage, such as magnesium-ion batteries, supercapacitors, and electrocatalysis.

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