Liu Shi-Wei, Niu Bai-Tong, Lin Bi-Li, Lin Yuan-Ting, Chen Xiao-Ping, Guo Hong-Xu, Chen Yan-Xin, Lin Xiu-Mei
College of Chemistry, Chemical Engineering and Environment, Minnan Normal University, Zhangzhou 363000, China.
State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou 350002, China.
Molecules. 2024 Aug 19;29(16):3912. doi: 10.3390/molecules29163912.
Transition metal oxides (TMOs) are important anode materials in sodium-ion batteries (SIBs) due to their high theoretical capacities, abundant resources, and cost-effectiveness. However, issues such as the low conductivity and large volume variation of TMO bulk materials during the cycling process result in poor electrochemical performance. Nanosizing and compositing with carbon materials are two effective strategies to overcome these issues. In this study, spherical MnFeO@xC nanocomposites composed of MnFeO inner cores and tunable carbon shell thicknesses were successfully prepared and utilized as anode materials for SIBs. It was found that the property of the carbon shell plays a crucial role in tuning the electrochemical performance of MnFeO@xC nanocomposites and an appropriate carbon shell thickness (content) leads to the optimal battery performance. Thus, compared to MnFeO@1C and MnFeO@8C, MnFeO@4C nanocomposite exhibits optimal electrochemical performance by releasing a reversible specific capacity of around 308 mAh·g at 0.1 A·g with 93% capacity retention after 100 cycles, 250 mAh·g at 1.0 A g with 73% capacity retention after 300 cycles in a half cell, and around 111 mAh·g at 1.0 C when coupled with a NaV(PO) (NVP) cathode in a full SIB cell.
过渡金属氧化物（TMOs）因其高理论容量、资源丰富和成本效益，成为钠离子电池（SIBs）中重要的负极材料。然而，TMO块状材料在循环过程中存在电导率低和体积变化大等问题，导致其电化学性能较差。纳米尺寸化以及与碳材料复合是克服这些问题的两种有效策略。在本研究中，成功制备了由MnFeO内核和可调碳壳厚度组成的球形MnFeO@xC纳米复合材料，并将其用作SIBs的负极材料。研究发现，碳壳的性质在调节MnFeO@xC纳米复合材料的电化学性能方面起着关键作用，合适的碳壳厚度（含量）可带来最佳的电池性能。因此，与MnFeO@1C和MnFeO@8C相比，MnFeO@4C纳米复合材料表现出最佳的电化学性能，在0.1 A·g下可逆比容量约为308 mAh·g，100次循环后容量保持率为93%；在半电池中，1.0 A g下300次循环后可逆比容量为250 mAh·g，容量保持率为73%；在全SIB电池中与NaV(PO)（NVP）正极耦合时，1.0 C下可逆比容量约为111 mAh·g。
