MXene, with metallic conductivity, strong hydrophilicity, and rich chemistries, has been widely used as electrode material for energy storage. However, the notorious issues of aggregation and oxidation for MXene significantly inhibit its electrochemical performance and further wide application. Herein, a physicochemical double protection strategy is proposed to stabilize MXene in the hydrothermal process effectively. Polyvinylpyrrolidone (PVP), with the structure of a long chain and abundant O/N function groups, provides physical protection against agglomeration (steric effect) and chemical protection against oxidation (electron transfer) at the same time, contributing to the synthesis of MXene-based hybrids with high conductivity and fully exposed active sites. As proof of the concept, 2D MXene/CoS nanohybrids with a scaly surface are fabricated and present impressive performance, especially rate performance for hybrid supercapacitor (HSC) with MoS as the counter electrode. The HSC demonstrates a high energy density of 111 Wh kg at 845 W kg and an excellent rate performance of 61 Wh kg at 16.9 kW kg.

中文翻译：

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物理化学双重保护使 MXene 能够稳定用于高性能混合超级电容器


MXene具有金属导电性、强亲水性和丰富的化学性质，已被广泛用作储能电极材料。然而，MXene众所周知的聚集和氧化问题严重抑制了其电化学性能和进一步广泛的应用。在此，提出了一种物理化学双重保护策略来有效稳定水热过程中的MXene。聚乙烯吡咯烷酮（PVP）具有长链结构和丰富的O/N官能团，同时提供防止团聚（空间效应）的物理保护和防止氧化（电子转移）的化学保护，有助于MXene-的合成基于具有高电导率和完全暴露的活性位点的杂化物。作为这一概念的证明，具有鳞片状表面的 2D MXene/CoS 纳米混合材料被制造出来，并呈现出令人印象深刻的性能，特别是以 MoS2 作为对电极的混合超级电容器 (HSC) 的倍率性能。 HSC 在 845 W kg 时表现出 111 Wh kg 的高能量密度，在 16.9 kW kg 时表现出 61 Wh kg 的优异倍率性能。