One-pot formation of ultra-thin Ni/Co hydroxides with a sheet-like structure for enhanced asymmetric supercapacitors
One-pot formation of ultra-thin Ni/Co hydroxides with a sheet-like structure for enhanced asymmetric supercapacitors
复制标题
DOI：
10.1039/c6ta02436j
复制
发表时间：
2016-06
影响因子：
--
通讯作者：
Lin Ye;Lijun Zhao;Hangzhou Zhang;Bo Zhang;Huiyuan Wang
中科院分区：
文献类型：
--
作者：
Lin Ye;Lijun Zhao;Hangzhou Zhang;Bo Zhang;Huiyuan Wang
在我们的工作中，通过一锅水热反应，成功地在导电泡沫镍表面生长了具有片状结构的超薄Ni/Co氢氧化物(Ni1Co2)，而不需要粘结剂和导电剂。在反应中，反应物中的NO3-−离子部分释放出OH-−离子，而Co2+离子转变为Co3+离子，然后在水和乙醇的混合溶剂中，OH-−+可以与Ni2+、Co2+或Co3+反应，而不需要额外的碱源。当用于超级电容器时，所得到的自支撑Ni1Co2复合材料在1 A g−1的电流密度下表现出令人印象深刻的2654.9 F g−1的比容和良好的循环稳定性，即使在1500次循环后的10 A g−1的高电流密度下仍保持77%的保持率。为了研究Ni1Co2复合材料的电化学性质，以Ni1Co2纳米片为正极，以活性碳(AC)为负极，构建了一种简单的非对称超级电容器。这种扩展电压窗口为0-1.6V的ASC具有42.4W h kg−1(功率密度为823.2 W kg−1)的出色能量密度，并仍保持24.8W h kg−1(10 170.8 W kg−1)。同时，该器件具有良好的循环稳定性，在电流密度为5A g−1的条件下，3 000次循环后的比电容保持率达94%。因此，Ni1Co2基复合材料有望成为一种潜在的高性能储能材料。
In our work, ultra-thin Ni/Co hydroxides (Ni1Co2) with a sheet-like structure are successfully grown on the surface of conductive nickel foam via a one-pot hydrothermal reaction, avoiding the need for binders and conducting agents. In the reaction, NO3− ions from reactants release OH− ions partially with Co2+ ions turning into Co3+ ions and then OH− ions can react with Ni2+, Co2+ or Co3+ in a mixed solvent of water and ethanol, without the necessary addition of an extra alkali source. When used for supercapacitors, the resulting free-standing Ni1Co2 composites exhibit an impressive specific capacitance of 2654.9 F g−1 at a current density of 1 A g−1 and a favorable cycling stability with 77% retention even at a high current density of 10 A g−1 after 1500 cycles. In order to do research into the electrochemical properties of Ni1Co2 composites, a simple asymmetric supercapacitor (ASC) is constructed, using the Ni1Co2 nanosheets as the positive electrode and activated carbon (AC) as the negative electrode. This ASC with an extended voltage window of 0–1.6 V presents an outstanding energy density of 42.4 W h kg−1 (at a power density of 823.2 W kg−1) and still retains 24.8 W h kg−1 (at 10 170.8 W kg−1). Meanwhile, the excellent cycling stability of this ASC device has been revealed via a great specific capacitance retention of 94% after 3000 cycles (at a current density of 5 A g−1). So the Ni1Co2-based composites could be one of the potential materials for high-performance energy storage.