MOFs (metal–organic frameworks) are widely utilized as both the templates and precursors to prepare nanomaterials as supercapacitor electrodes. However, traditional thermolysis routes are difficult to control and usually lead to collapse of the MOF skeletons, which hinders wider applications. Herein, we describe a simple and facile strategy for fabricating the Ni(OH)₂ hierarchical structure by the “conformal transformation” of one particular Ni-MOF through hydrolysis in the KOH aqueous solution. By controlling the concentration of KOH solution and the soaking time, the obtained Ni(OH)₂ nanomaterial possesses both optimized crystallinity and porosity, extremely beneficial for electron transportation and ion migration within the electrodes. Taking these advantages, the Ni(OH)₂ electrode presents a remarkable specific capacity of 830.6 C g⁻¹, and the fabricated all-solid state asymmetric supercapacitor presents a remarkable energy density of 37.8 W h kg⁻¹ at a power density of 252.67 W kg⁻¹, which surpasses most Ni(OH)₂ based supercapacitor devices. After 15 000 cycles, the capacitance remains at over 93% of the initial value.

中文翻译：

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通过金属-有机骨架模板的保形转化， 优化分级Ni（OH）_2的结晶度和孔隙率，以用于超级电容器应用†

MOF（金属有机框架）被广泛用作模板和前体，以制备纳米材料作为超级电容器电极。但是，传统的热解路线难以控制，通常会导致MOF骨架塌陷，从而阻碍了更广泛的应用。在本文中，我们描述了一种简单而又容易实现的策略，该方法通过在KOH水溶液中水解来对一种特定的Ni-MOF进行“共形转化”，从而制造Ni（OH）₂分层结构。通过控制KOH溶液的浓度和浸泡时间，获得的Ni（OH）₂纳米材料具有优化的结晶度和孔隙率，对电极内的电子传输和离子迁移极为有利。利用这些优势，Ni（OH）₂电极具有830.6 C g ^-1的显着比电容，制造的全固态非对称超级电容器在252.67 W kg ^-1的功率密度下具有37.8 W h kg ^-1的显着能量密度，超过了大多数Ni基于（OH） ₂的超级电容器设备。在15 000次循环之后，电容保持在初始值的93％以上。