In this work, we report the structure-dependent electrochemical performance of cobalt carbonate hydroxide (Co₂(OH)₂CO₃) nanocrystals by experimental investigation and theoretical simulation. Different Co₂(OH)₂CO₃ nanostructures including two-dimensional (2D) nanosheets (NSs) and one-dimensional (1D) nanowires (NWs), were synthesized on self-supported carbon cloth substrates by a facile hydrothermal method. Compared to 1D NWs, 2D Co₂(OH)₂CO₃ NSs provided a short ion transfer path, and low electron transfer resistance during the electrochemical reaction. At the current density of 2 mA cm⁻², 2D Co₂(OH)₂CO₃ NSs exhibited a higher area capacitance of 2.15F cm⁻² and better cycling performance (96.2% retention after 10,000 cycles) than that of 1D NWs (1.15F cm⁻² and 90.1% retention). First-principles density functional theory (DFT) calculations revealed that the band gap of the (1 2 0) facet in 2D NSs was 0.2 eV, far less than of the (2 0 0) facet in 1D NWs (1.04 eV). Electrochemical impedance spectroscopy (EIS) measurements further indicated that the electron transfer and reaction kinetics were more efficient in 2D NSs. This work can provide an important insight in understanding the mechanism of electrochemical energy storage.

在这项工作中，我们通过实验研究和理论模拟报告了碳酸钴氢氧化物（Co ₂ (OH) ₂ CO ₃）纳米晶体的结构相关电化学性能。不同的 Co ₂ (OH) ₂ CO ₃纳米结构包括二维 (2D) 纳米片 (NSs) 和一维 (1D) 纳米线 (NWs)，通过简便的水热法在自支撑碳布基材上合成。与一维纳米线相比，二维 Co ₂ (OH) ₂ CO ₃ NSs 在电化学反应过程中提供了较短的离子转移路径和较低的电子转移电阻。在电流密度为 2 mA cm ^-2, 2D Co ₂ (OH) ₂ CO ₃ NSs 表现出比 1D NWs（1.15F cm ^-2和 90.1% 保留率）更高的面积电容 2.15F cm ^-2和更好的循环性能（10,000 次循环后保留率 96.2% ） . 第一性原理密度泛函理论 (DFT) 计算表明，2D NSs 中(1 2 0) 面的带隙为 0.2 eV，远小于1D NW 中 ( 2 0 0) 面的带隙(1.04 eV)。电化学阻抗谱 (EIS) 测量进一步表明电子转移和反应动力学在 2D NSs 中更有效。这项工作可以为理解电化学储能机制提供重要的见解。