阳极
材料科学
微型多孔材料
碳纤维
电化学
化学工程
硒化物
硒化锌
电导率
密度泛函理论
纳米技术
复合数
化学
电极
复合材料
光电子学
物理化学
计算化学
工程类
冶金
硒
作者
Jiafeng Ruan,Jiahe Zang,Jun Hu,Renchao Che,Fang Fang,Fei Wang,Yun Song,Dalin Sun
标识
DOI:10.1002/advs.202104822
摘要
Potassium-ion batteries (PIBs) have been considered as potential alternatives for lithium-ion batteries since there is a demand for better anode with superior energy, excellent rate capability, and long cyclability. The high-capacity zinc selenide (ZnSe) anode, which combines the merits of conversion and alloying reactions, is promising for PIBs but suffers from poor cyclability and low electronic conductivity. To effectively boost electrochemical performance of ZnSe, a "dual-carbon-confined" structure is constructed, in which an inner N-doped microporous carbon (NMC)-coated ZnSe wrapped by outer-rGO (ZnSe@i-NMC@o-rGO) is synthesized. Combining finite element simulation, dynamic analysis, and density functional theory calculations, the respective roles of inner- and outer-carbon in boosting performance are revealed. The inner-NMC increased the reactivity of ZnSe with K+ and alleviated the volume expansion of ZnSe, while outer-rGO further stabilized the structure and promoted the reaction kinetics. Benefiting from the synergistic effect of dual-carbon, ZnSe@i-NMC@o-rGO exhibited a high specific capacity 233.4 mAh g-1 after 1500 cycles at 2.0 A g-1 . Coupled with activated carbon, a potassium-ion hybrid capacitor displayed a high energy density of 176.6 Wh kg-1 at 1800 W kg-1 and a superior capacity retention of 82.51% at 2.0 A g-1 after 11000 cycles.
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