杂原子
阳极
介电谱
材料科学
电化学
碳纤维
电解质
X射线光电子能谱
化学工程
循环伏安法
化学
无机化学
电极
有机化学
戒指(化学)
复合材料
复合数
工程类
物理化学
作者
Dingyu Nan,Zhicai Wu,Zhiyong Lu,Lei Qin,Chao Zhang,Liang Chen,Ding Zhang,Shoudong Xu
标识
DOI:10.1016/j.electacta.2023.143019
摘要
Potassium-ion storage devices have gained increasing interest in applications such as large-scale energy storage and smart grids due to the advantages of high abundance, low cost, high working voltage, and fast charge transport in electrolytes. However, obtaining high-performance anodes with excellent rate performance and cycling stability remains a challenge due to the much larger size of K+ ions. In this contribution, heteroatom S doped dumbbell-like hard carbon (SDHC) are synthesized using sucrose as the carbon source. SDHC-700, which is carbonized at 700 °C, exhibits the highest sulfur doping degree (9.3 at.%), remarkable reversible capacity (416 mAh g-1 at 0.05 A g-1), and superb rate performance (174 mAh g-1 at 5.0 A g-1). Ex situ X-ray photoelectron spectroscopy (XPS) tests reveal that covalent C-S bonds can undergo a reversible reaction with K to form K2Sx. In situ electrochemical impedance spectroscopy (EIS) results suggest that the diffusion of long-chain potassium polysulfides may be the main reason for the degradation of SDHC during long-term cycling. Moreover, using SDHC-700 as the anode and commercial activated carbon as the cathode, a dual-carbon potassium-ion hybrid capacitor has been successfully constructed, which can deliver a high energy/power density of 96.5 Wh kg-1/160.3 W kg-1. This study provides a straightforward and practical approach for developing sulfur-doped hard carbons as high-performance anode materials for alkali metal ion storage.
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