Ammonium vanadate with bronze structure(NH_(4)V_(4)O_(10))is a promising cathode material for zinc-ion batteries due to its high specific capacity and low cost.However,the extraction of NH^(+)_(4) at a high voltage du...Ammonium vanadate with bronze structure(NH_(4)V_(4)O_(10))is a promising cathode material for zinc-ion batteries due to its high specific capacity and low cost.However,the extraction of NH^(+)_(4) at a high voltage during charge/discharge processes leads to irreversible reaction and structure degradation.In this work,partial NH^(+)_(4) ions were pre-removed from NH_(4)V_(4)O_(10) through heat treatment;NH_(4)V_(4)O_(10) nanosheets were directly grown on carbon cloth through hydrothermal method.Defi-cient NH_(4)V_(4)O_(10)(denoted as NVO),with enlarged interlayer spacing,facilitated fast zinc ions transport and high storage capacity and ensured the highly reversible electrochemical reaction and the good stability of layered structure.The NVO nanosheets delivered a high specific capac-ity of 457 mAh g^(−1) at a current density of 100 mA g^(−1) and a capacity retention of 81%over 1000 cycles at 2 A g^(−1).The initial Coulombic efficiency of NVO could reach up to 97%compared to 85%of NH_(4)V_(4)O_(10) and maintain almost 100%during cycling,indicating the high reaction reversibility in NVO electrode.展开更多
过渡金属磷化物具有高电导率和高电化学活性,是一类新兴的混合电容器电极材料.然而制备具有快速反应动力学和稳定结构的过渡金属磷化物仍然是一大挑战.本文将Mo或W引入到Ni CoP中,得到具有三维开放结构的纳米阵列和优化电子结构的异质结...过渡金属磷化物具有高电导率和高电化学活性,是一类新兴的混合电容器电极材料.然而制备具有快速反应动力学和稳定结构的过渡金属磷化物仍然是一大挑战.本文将Mo或W引入到Ni CoP中,得到具有三维开放结构的纳米阵列和优化电子结构的异质结构.相比于NiCo P纳米阵列,Ni-Co-Mo-P或Ni-Co-W-P纳米阵列具有更大的比表面积和更多的空隙,这种独特的结构不仅有助于电解液的渗透,还可以缓解氧化还原过程中的体积变化.密度泛函理论计算结果显示引入高价Mo或W元素形成异质结构提高了材料的本征电导率,加快了反应动力学.Ni-Co-Mo-P纳米阵列在2 m A cm^(-2)的电流密度下表现出4.08 C cm^(-2)(703 C g^(-1))的高面积比容量;在30 m A cm^(-2)下,比容量还能保持在3.25 C cm^(-2).此外,Ni-Co-Mo-P纳米阵列与活性炭组装成的水系混合超级电容器表现出800 W kg^(-1)的高能量密度.本研究为高性能过渡金属磷化物基电极材料的设计拓宽了思路,有助于促进其在混合电容器中的应用.展开更多
基金This work was supported by the National Science Foundation(CBET-1803256)National Natural Science Foundation of China(Grant No.51772267)+3 种基金the National Key R&D Program of China(Grant No.2016YFB0401501)the Key R&D Program of Zhejiang Province(Grant No.2020C01004)The author acknowledges the financial support from China Scholarship Council(No.201906320198)2019 Zhejiang University Academic Award for Outstanding Doctoral Candidates.
文摘Ammonium vanadate with bronze structure(NH_(4)V_(4)O_(10))is a promising cathode material for zinc-ion batteries due to its high specific capacity and low cost.However,the extraction of NH^(+)_(4) at a high voltage during charge/discharge processes leads to irreversible reaction and structure degradation.In this work,partial NH^(+)_(4) ions were pre-removed from NH_(4)V_(4)O_(10) through heat treatment;NH_(4)V_(4)O_(10) nanosheets were directly grown on carbon cloth through hydrothermal method.Defi-cient NH_(4)V_(4)O_(10)(denoted as NVO),with enlarged interlayer spacing,facilitated fast zinc ions transport and high storage capacity and ensured the highly reversible electrochemical reaction and the good stability of layered structure.The NVO nanosheets delivered a high specific capac-ity of 457 mAh g^(−1) at a current density of 100 mA g^(−1) and a capacity retention of 81%over 1000 cycles at 2 A g^(−1).The initial Coulombic efficiency of NVO could reach up to 97%compared to 85%of NH_(4)V_(4)O_(10) and maintain almost 100%during cycling,indicating the high reaction reversibility in NVO electrode.
基金financially supported by the National Natural Science Foundation of China (51772267)the Science and Technology Program of Guangxi Zhuang Autonomous Region (ZD20302001)。
文摘过渡金属磷化物具有高电导率和高电化学活性,是一类新兴的混合电容器电极材料.然而制备具有快速反应动力学和稳定结构的过渡金属磷化物仍然是一大挑战.本文将Mo或W引入到Ni CoP中,得到具有三维开放结构的纳米阵列和优化电子结构的异质结构.相比于NiCo P纳米阵列,Ni-Co-Mo-P或Ni-Co-W-P纳米阵列具有更大的比表面积和更多的空隙,这种独特的结构不仅有助于电解液的渗透,还可以缓解氧化还原过程中的体积变化.密度泛函理论计算结果显示引入高价Mo或W元素形成异质结构提高了材料的本征电导率,加快了反应动力学.Ni-Co-Mo-P纳米阵列在2 m A cm^(-2)的电流密度下表现出4.08 C cm^(-2)(703 C g^(-1))的高面积比容量;在30 m A cm^(-2)下,比容量还能保持在3.25 C cm^(-2).此外,Ni-Co-Mo-P纳米阵列与活性炭组装成的水系混合超级电容器表现出800 W kg^(-1)的高能量密度.本研究为高性能过渡金属磷化物基电极材料的设计拓宽了思路,有助于促进其在混合电容器中的应用.
