posted on 2021-05-26, 18:25authored byYu 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.