氢氧化物
层状双氢氧化物
材料科学
自行车
超级电容器
插层(化学)
电化学
镍
层状结构
化学工程
钴
离子
电极
剥脱关节
无机化学
纳米技术
化学
复合材料
石墨烯
冶金
有机化学
考古
物理化学
工程类
历史
作者
Wenxuan Hu,Lu Chen,Biao Geng,Yihu Song,Ziliang Wu,Qiang Zheng,Guorong Shan,Ming Du
标识
DOI:10.1016/j.cej.2023.143694
摘要
Layered double hydroxides (LDHs), a class of 2D lamellar intercalating materials, is a promising candidate for high-performance supercapacitors, while its poor cycling stability has always been its Achille’s heel. Although doping metal ions into the host layer is proved to be an effective way to improve the weakness, the effects of intercalated anions on cycling performance have been rarely studied and highly underestimated. In this paper, we prepared a group of NiCo-LDHs with different intercalated anions, including NO3−, Cl−, SO42−, MoO42− and WO42−, which expand the interlayer spacing from 0.73 to 1.07 nm. Interestingly, although expanding the interlayer spacing could increase the specific capacity by providing more electrochemical active sites, it could not guarantee the improvement in cycling performance and rate capability. The correlation between interlayer spacing and cycling performance exhibits a “volcano” plot. The MoO42− intercalated NiCo-LDH with a 0.96 nm interlayer spacing delivers a high specific capacity of 795 C g−1 and the best cycling stability with 80% capacity retention after 20,000 cycles, which is better than NiCo-LDH-NO3 (0.73 nm, 50% after 3000 cycles) and NiCo-LDH-WO4 (1.07 nm, 64% after 20,000 cycles). By combining the results with the DFT method, the effects of intercalated anion on cycling performance are illustrated. In addition, the asymmetric supercapacitor also exhibits an excellent cycling stability with ∼100% capacity retention after 10,000 cycles. This study provides new insight to the compositional design of LDH-based electrodes for long-lifespan supercapacitors.
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