Aqueous ammonium-ion (NH) supercapacitors (AASCs) have recently garnered increased concerns but are consistently facing the challenge of lower energy density. Herein, a high-performance electrode (CuCoS@CP) with pseudocapacitive property has been synthesized and primordially applied to AASCs. The CuCoS@CP electrode has an ultrahigh specific capacity of 1512 C g at 1 A g and a distinguished cyclic stability of 87.74 % after 10,000 cycles. When the CuCoS@CP electrode is combined with the activated carbon (AC) negative electrode, the CuCoS@CP//AC device exhibits a high specific capacity of 547 C g at 1 A g, excellent cycle stability (83.28 % at 10 A g), high energy density of 74.17 Wh kg, and excellent device consistency. In addition, the charge transfer mechanism of CuCoS@CP electrode in NHelectrolyte has been elucidated. The CuCoS surface density functional theory (DFT) elucidates that NH has a minimal contribution to the surface, implying an insertion behavior of NH within the CuCoS lattice. Subsequent characterization further confirms the energy storage process, revealing charge transfer to Co atoms following NH insertion into CuCoS. The analysis of charge distribution illustrates an energy storage mechanism wherein the hydrogen bond formed between NH and CuCoS serves as the transport channel for charge transfer, facilitating the process of electrons from NH to Co atoms. Therefore, the pseudocapacitive mechanism of CuCoS with NH provides a blueprint for sustainable energy storage with high energy density in aqueous electrolyte.

中文翻译：

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深入了解具有优异能量密度和循环能力的水铵离子超级电容器的赝电容机制


水性铵离子（NH）超级电容器（AASC）最近引起了越来越多的关注，但始终面临能量密度较低的挑战。本文合成了一种具有赝电容特性的高性能电极（CuCoS@CP），并首次应用于AASC。 CuCoS@CP电极在1 A g-1下具有1512 C g-1的超高比容量，并且在10,000次循环后具有87.74%的出色循环稳定性。当CuCoS@CP电极与活性炭（AC）负极结合时，CuCoS@CP//AC器件表现出1 A g下547 C g的高比容量，优异的循环稳定性（10 A g下83.28％） ），能量密度高达74.17 Wh kg，器件一致性优异。此外，还阐明了CuCoS@CP电极在NH电解质中的电荷转移机制。 CuCoS 表面密度泛函理论 (DFT) 阐明 NH 对表面的贡献最小，这意味着 NH 在 CuCoS 晶格内的插入行为。随后的表征进一步证实了能量存储过程，揭示了 NH 插入 CuCoS 后电荷转移到 Co 原子。电荷分布分析说明了一种能量存储机制，其中 NH 和 CuCoS 之间形成的氢键充当电荷转移的传输通道，促进电子从 NH 到 Co 原子的过程。因此，CuCoS与NH的赝电容机制为水性电解质中高能量密度的可持续储能提供了蓝图。