MnS/MnO heterostructures with dual ion defects for high-performance aqueous magnesium ion capacitors

作者：Minghui Liu, Mudi Li, Siwen Zhang, Yaxi Ding, Ying Sun, Jiazhuo Li, Haixi Gu, Bosi Yin, Hui Li, Tianyi Ma · 发表于：Journal of Magnesium and Alloys · 年份：2024 · DOI：10.1016/j.jma.2024.04.036 · 被引用次数：20 · 研究领域：Supercapacitor Materials and Fabrication、Advanced battery technologies research、Advancements in Battery Materials

The advancement of aqueous magnesium ion energy storage devices encounters limitations due to the substantial hydration radius of magnesium ions (Mg2+) and their strong electrostatic interaction with the primary material. Consequently, this study successfully developed a MnS/MnO heterostructure through a straightforward hydrothermal and annealing method, marking its initial application in aqueous magnesium ion capacitors (AMICs). The fabricated MnS/MnO heterostructure, characterized by S defects, also generates Mn defects via in-situ initiation of early electrochemical processes. This unique dual ion defects MnS/MnO heterostructure (DID-MnS/MnO) enables the transformation of MnS and MnO, initially not highly active electrochemically for Mg2+, into cathode materials exhibiting high electrochemical activity and superior performance. Moreover, DID-MnS/MnO enhances conductivity, improves the kinetics of surface redox reactions, and increases the diffusion rate of Mg2+. Furthermore, this study introduces a dual energy storage mechanism for DID-MnS/MnO, which, in conjunction with dual ion defects, offers additional active sites for Mg2+ insertion/deinsertion in the host material, mitigating volume expansion and structural degradation during repeated charge-discharge cycles, thereby significantly enhancing cycling reversibility. As anticipated, using a three-electrode system, the developed DID-MnS/MnO demonstrated a discharge specific capacity of 237.9 mAh/g at a current density of ...