Wu Tzu Ho, Yen Li Hsuan, Lin Ya Qi
Department of Chemical and Materials Engineering, National Yunlin University of Science and Technology, 123 University Road, Section 3, Douliou, Yunlin 64002, Taiwan.
Department of Chemical and Materials Engineering, National Yunlin University of Science and Technology, 123 University Road, Section 3, Douliou, Yunlin 64002, Taiwan.
J Colloid Interface Sci. 2022 Nov;625:354-362. doi: 10.1016/j.jcis.2022.06.033. Epub 2022 Jun 9.
Rechargeable aqueous zinc-ion batteries (RAZIBs) show great potential as a competitive candidate for reliable energy storage by virtue of cost-effectiveness, high safety, and environmental friendliness. However, unsatisfactory cycle stability of cathode material impedes the development of high-performance RAZIBs. This study reveals a strategic polyol-mediated process by using glycerol as the solvent for solvothermal reaction. After heat treatment in air, Mn-deficient MnO spinel (D-MnO) can be obtained with rich Mn valence states (Mn/Mn/Mn), expanded crystal structure, high surface area, and good electrolyte compatability. Compared to well-crystallized MnO, the presence of manganese vacancies in D-MnO enables lower charge-transfer resistance (86.0 vs 196.5 Ω), reduced activation energy for ion insertion (30.9 vs 50.4 kJ mol), and boosted solid-state ion diffusivity (9.45 × 10 vs 4.61 × 10 cm s). Therefore, D-MnO exhibits promising electrochemical performance with high capacity (284 mAh g), high specific energy (388.5 Wh kg) and stable cycle retention (87% after 200 cyclesat 0.3 A g). On the contrary, the well-crystallized MnO sample suffers from severe capacity fading with only 48% capacity retention. Moreover, the specific energies obtained after 200 cycles are 336.1 and 166.0 Wh kg for D-MnO and MnO, respectively. The drastic differences between the electrochemical performance of D-MnO and MnO manifest that the existing manganese vacancies in MnO spinel structure enhance energy storage capability.
可充电水系锌离子电池（RAZIBs）凭借成本效益高、安全性高和环境友好等优势，作为可靠储能的有竞争力候选者展现出巨大潜力。然而，阴极材料不尽人意的循环稳定性阻碍了高性能RAZIBs的发展。本研究揭示了一种以甘油为溶剂进行溶剂热反应的策略性多元醇介导过程。在空气中热处理后，可以获得具有丰富锰价态（Mn/Mn/Mn）、扩展晶体结构、高表面积和良好电解质相容性的缺锰MnO尖晶石（D-MnO）。与结晶良好的MnO相比，D-MnO中锰空位的存在使得电荷转移电阻更低（86.0对196.5Ω），离子插入的活化能降低（30.9对50.4kJ mol），固态离子扩散率提高（9.45×10对4.61×10 cm s）。因此，D-MnO表现出具有高容量（284 mAh g）、高比能量（388.5 Wh kg）和稳定循环保持率（在0.3 A g下200次循环后为87%）的有前景的电化学性能。相反，结晶良好的MnO样品容量严重衰减，仅保留48%的容量。此外，D-MnO和MnO在200次循环后获得的比能量分别为336.1和166.0 Wh kg。D-MnO和MnO电化学性能的巨大差异表明MnO尖晶石结构中现有的锰空位增强了储能能力。
