Owing to quantum size effect and high redox activity, quantum dots (QDs) play very essential roles toward electrochemical energy storage. However, it is very difficult to obtain different‐type and uniformly dispersed high‐active QDs in a stable conductive microenvironment, because QDs prepared by traditional methods are mostly dissolved in solution or loaded on the surface of other semiconductors. Herein, dual‐type semiconductor QDs (Co9S8 and CdS) are skillfully constructed within the interlayer of ultrathin layered double hydroxides (LDH). In particular, the expandable interlayer provides a very suitable confined space for the growth and uniform dispersion of QDs, where Co9S8 originates from in‐situ transformation of cobalt atoms in laminate and CdS is generated from interlayer pre‐embedding Cd2+. Meanwhile, XAFS and GGA+U calculations are employed to explore and prove the mechanism of QDs formation and energy storage characteristics as compared to surface loading QDs. Significantly, the hybrid supercapacitors achieve high energy density of 329.2 μWh cm−2, capacitance retention of 99.1% and coulomb efficiency of 96.9% after 22,000 cycles, which is superior to the reported QDs‐based supercapacitors. These findings provide unique insights for designing and developing stable, ordered, and highly active QDs.This article is protected by copyright. All rights reserved

中文翻译：

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用于高速电化学储能的有限空间双型量子点


由于量子尺寸效应和高氧化还原活性，量子点（QD）在电化学储能方面发挥着非常重要的作用。然而，由于传统方法制备的量子点大多溶解在溶液中或负载在其他半导体的表面上，因此很难在稳定的导电微环境中获得不同类型且均匀分散的高活性量子点。在此，双型半导体量子点（Co9S8 和 CdS）巧妙地构建在超薄层状双氢氧化物（LDH）的夹层内。特别是，可膨胀的中间层为量子点的生长和均匀分散提供了非常合适的有限空间，其中Co9S8源自层压板中钴原子的原位转变，而CdS则由层间预嵌入Cd2+生成。同时，采用XAFS和GGA+U计算来探索和证明量子点的形成机制以及与表面负载量子点相比的储能特性。值得注意的是，混合超级电容器在22,000次循环后实现了329.2 μWh cm−2的高能量密度、99.1%的电容保持率和96.9%的库仑效率，优于报道的基于量子点的超级电容器。这些发现为设计和开发稳定、有序和高活性的量子点提供了独特的见解。本文受版权保护。版权所有