材料科学
阳极
化学工程
插层(化学)
法拉第效率
碳纤维
熔盐
超级电容器
钾
兴奋剂
储能
纳米技术
无机化学
电化学
电极
复合材料
复合数
化学
冶金
物理化学
功率(物理)
光电子学
工程类
物理
量子力学
作者
Qingdi Liu,Fei Han,Jiafu Zhou,Yan Li,Long Chen,Fuquan Zhang,Dawei Zhou,Chong Ye,Jianxiao Yang,Xinming Wu,Jinshui Liu
标识
DOI:10.1021/acsami.0c00679
摘要
Soft carbon is attracting tremendous attention as a promising anode material for potassium-ion batteries (PIBs) because of its graphitizable structure and adjustable interlayer distance. Herein, nitrogen/sulfur dual-doped porous soft carbon nanosheets (NSC) have been prepared with coal tar pitch as carbon precursors in an appropriate molten salt medium. The molten salt medium and N/S dual-doping are responsible for the formation of nanosheet-like morphology, abundant microporous channels with a high surface area of 436 m2 g–1, expanded interlamellar spacing of 0.378 nm, and enormous defect-induced active sites. These structural features are crucial for boosting potassium-ion storage performance, endowing the NSC to deliver a high potassiation storage capacity of 359 mAh g–1 at 100 mA g–1 and 115 mAh g–1 at 5.0 A g–1, and retaining 92.4% capacity retention at 1.0 A g–1 after 1000 cycles. More importantly, the pre-intercalation of K atom from the molten salts helps improve the initial Coulombic efficiency to 50%, which outperforms those of the recently reported carbon anode materials with large surface areas. The density functional theory calculations further illuminate that the N/S dual-doping can facilitate the adsorption of K-ion in carbon materials and decrease the ion diffusion energy barrier during the solid-state charge migration.
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