Sodium/potassium ion based hybrid capacitors have recently attracted tremendous attention owing to their unique features of combining high-energy battery and high-power capacitor, as well as lower cost compared to Li⁺ based energy storage techniques. However, the exploitation of promising anode candidates featuring both high specific capacity and fast charge/discharge capability remains an urgent task. Herein, we present a promising anode host composed of MoSe₂ grafted carbonaceous nanotubes (denoted as MoSe₂-G-CNTs) through a sacrificing nanowire catalyzed polymerization process followed by conventional selenization treatment. The resultant MoSe₂-G-CNTs exhibit a superior K⁺ storage capability with a high reversible capacity (321.7 mAh g^–1 at 0.1 A g^–1) and long cycling stability (188 mAh g^–1 after 2000 cycles at 1.0 A g^–1). The possible origins of the remarkable performance are unraveled on the basis of the in situ Raman spectrum and galvanostatic intermittent titration (GITT) techniques. Importantly, the potassium ion hybrid capacitors (KIHCs) based on MoSe₂-G-CNTs anode can deliver a decent energy density of 109.8 Wh kg^–1 at a power density of 462.3 W kg^–1 with a long lifespan up to 6000 cycles. This work could not only provide a design rationale for advanced hybrid nanostructures but also steer the boom of energy storage devices based on earth-abundant alkaline metals.

中文翻译：

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牺牲纳米线催化聚合过程产生分级 MoSe2 接枝碳质纳米管，用于优异的钾离子存储

钠/钾离子的基于混合电容器最近已引起极大的关注由于其结合高能量电池和高功率电容器，以及相比李较低成本的独特特征⁺基于能量储存技术。然而，开发具有高比容量和快速充电/放电能力的有前景的候选负极仍然是一项紧迫的任务。在此，我们通过牺牲纳米线催化聚合工艺和常规硒化处理，提出了一种有前途的阳极主体，由 MoSe ₂接枝的碳质纳米管（表示为 MoSe ₂ -G-CNT）组成。所得的 MoSe ₂ -G-CNTs 表现出优异的 K ⁺具有高可逆容量（321.7 mAh g ^–1在 0.1 A g ^–1）和长循环稳定性（188 mAh g ^–1在 1.0 A g ^{–1 下}2000 次循环后）的存储能力。基于原位拉曼光谱和恒电流间歇滴定 (GITT) 技术，揭示了卓越性能的可能起源。重要的是，基于 MoSe ₂ -G-CNTs 阳极的钾离子混合电容器 (KIHC)可以在 462.3 W kg ^–1的功率密度下提供 109.8 Wh kg ^–1的不错能量密度使用寿命长达6000次循环。这项工作不仅可以为先进的混合纳米结构提供设计原理，还可以引导基于地球上丰富的碱金属的储能设备的繁荣。