State Key Laboratory of Chemical Physics of Solid Surfaces, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China.
Department of Metallurgical and Materials Engineering, Indian Institute of Technology Jodhpur, Jodhpur 342030, India.
ACS Appl Mater Interfaces. 2023 Apr 19;15(15):18819-18827. doi: 10.1021/acsami.2c22848. Epub 2023 Apr 6.
FeO is one of the most common anode materials beyond carbons but suffers from unsatisfactory capacity and poor stability, which are associated with the insufficient utilization of active material and the structural instability caused by the phase transformation. In this work, we report an effective strategy to overcome the above issues through electronic structure optimization by constructing delicately designed FeO@VN core-shell structure. The FeO@VN/CC exhibits a much higher areal capacity of 254.8 mC cm at 5 mA cm (corresponding to 318.5 mF cm, or 265.4 F g) than the individual VN (48 mC cm, or 60 mF cm) or FeO/CC (93.36 mC cm, or 116.7 mF cm), along with enhanced stability. Moreover, the assembled asymmetric supercapacitor devices based on FeO@VN/CC anode and RuO/CC cathode show a high stack energy density of 0.5 mWh cm at a power density of 12.28 mW cm along with good stability (80% capacitance retention after 14000 cycles at 10 mA cm). This work not only establishes the FeO@VN as a high-performance anode material but also suggests a general strategy to enhance the electrochemical performance of traditional anodes that suffer from low capacity (capacitance) and poor stability.
FeO 是除碳以外最常用的阳极材料之一，但由于活性材料的利用率不足和相变引起的结构不稳定，其容量和稳定性都不尽人意。在这项工作中，我们通过构建精心设计的 FeO@VN 核壳结构来优化电子结构，从而报告了一种克服上述问题的有效策略。FeO@VN/CC 表现出比单独的 VN（48 mC cm，或 60 mF cm）或 FeO/CC（93.36 mC cm，或 116.7 mF cm）更高的面积容量，为 254.8 mC cm，在 5 mA cm 下（对应于 318.5 mF cm，或 265.4 F g），以及增强的稳定性。此外，基于 FeO@VN/CC 阳极和 RuO/CC 阴极的组装非对称超级电容器器件在 12.28 mW cm 的功率密度下具有 0.5 mWh cm 的高堆叠能量密度，以及良好的稳定性（在 10 mA cm 下循环 14000 次后保持 80%的电容）。这项工作不仅确立了 FeO@VN 作为一种高性能的阳极材料，而且还提出了一种增强传统阳极的电化学性能的通用策略，这些传统阳极的容量（电容）低，稳定性差。
