In asymmetric supercapacitors, transition metal selenates are promising electrodes, but their capacity are limited by a single redox center. To further enhance the performance of transition metal selenates, Ni_xCo_1−xSeO₃ (NCSeO) doped with N and Cl was prepared on nickel-plated carbon cloth (NCSeO–NCl–NiCC). During electrochemical reactions, NCSeO can be converted to M(OH)₂ (M = Ni/Co) and OH⁻ is replaced by N and Cl. Two redox centers, M(OH)₂/MOOH and M(OH)_xN_2−x/NO₃⁻, are formed during charging and discharging, which is attributed to the increased capacity of the NCSeO–NCl–NiCC electrode. On NCSeO, the substitution of Cl facilitates the regulation of the electronic structure and enhances the stability of N-doping. The optimised electrode exhibits a high capacity of 417 mA h g⁻¹ at 1 A g⁻¹ and an impressive rate capability of 235 mA h g⁻¹ at 50 A g⁻¹. Asymmetric supercapacitors with this design have an ultra-high energy density of 73.6 W h kg⁻¹, as well as an excellent rate and cycling performance with a capacitance retention of 97.8% after 20 000 cycles at a current density of 20 A g⁻¹.

中文翻译：

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通过 NixCo1−xSeO3 中双氧化还原中心的阴离子掺杂结构实现高容量水系超级电容器


在不对称超级电容器中，过渡金属硒酸盐是有前途的电极，但它们的容量受到单个氧化还原中心的限制。为了进一步提高过渡金属硒酸盐的性能，在镀镍碳布上制备了掺杂N和Cl的Ni _x Co _1−x SeO ₃ (NCSeO) （NCSeO-NCl-NiCC）。在电化学反应过程中，NCSeO可以转化为M(OH) ₂ (M = Ni/Co)，并且OH ⁻ 被N和Cl取代。两个氧化还原中心，M(OH) ₂ /MOOH 和 M(OH) _x N _2−x /NO ₃ ⁻ 下表现出 417 mAh g ⁻¹ 的高容量，在 50 A g ⁻¹ 下表现出 235 mAh g ⁻¹ 的令人印象深刻的倍率能力 < b13> 。采用该设计的非对称超级电容器具有73.6 W·h·kg ⁻¹ 的超高能量密度，以及优异的倍率和循环性能，在电流密度为20 000次循环后，电容保持率为97.8%。 20 克 ⁻¹ 。