α-MoO3水系氢离子电池储能性能研究
Study on electrochemical performances of α-MoO3 for aqueous hydrogen-ion batteries
凭借较低的电极电势以及较高的理论容量,层状结构的三氧化钼(α-MoO3)常作为负极材料应用于水系氢离子电池中,然而溶解流失问题导致其使用寿命较短。采用新型植酸电解液并优化使用条件,可有效解决上述问题。植酸能够降低电解液中的自由水活度,抑制水分子对α-MoO3晶格的腐蚀;控制充电电位能够避免与溶解流失有关的副反应的发生。因此,在 0.5 mol/L植酸水性电解液中,经充电电位优化后,α-MoO3电极具有188 mAh/g的可逆容量;在80 C下,倍率性能为56%;经 5 000次测试后,循环稳定性保持率100%。基于X射线粉末衍射技术的储能机理分析表明,α-MoO3在充放电过程中经历多次相变反应,仅钼青铜Ⅱ相与Ⅲ相间的反应是可逆的。
Layered molybdenum trioxide (α-MoO3) is one of the anode materials for aqueous hydrogen-ion batteries due to a lower electrode potential and a higher theoretical capacity.However,the dissolution loss resulting from it poses a severe challenge to a long lifespan.Herein,the above issue is solved by developing a phytic acid aqueous electrolyte together with the optimization of operation conditions.Phytic acid lowers the activity of free water in the aqueous electrolyte,which avoids the corrosion of water molecules to α-MoO3 lattice;controlling upper potential cutoff can suppress the parasitic reactions related to dissolution loss.As a result,after the optimization of upper potential cutoff,the α-MoO3 electrode delivers a specific capacity of 188 mAh/g in the phytic acid aqueous electrolyte with a molarity of 0.5 mol/L;its rate capability is measured to be 56% at 80 C;a 100% retention is obtained upon 5 000 cycles.The analysis of charge storage mechanisms based on X-ray powder diffractometry reveals that α-MoO3 undergoes multiple phase transition reactions during charge-discharge processes where only the reaction between molybdenum bronze Ⅱ and Ⅲ phases is reversible.
三氧化钼 / 溶解流失 / 循环稳定性 / 氢离子电池 / 电解液
molybdenum trioxide / dissolution loss / cycling stability / hydrogen-ion batteries / electrolytes
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辽宁省自然科学基金(2023-BS-173)
辽宁省教育厅基本科研项目(LJKQZ20222291)
大连工业大学高层次人才科研启动资金(LJBKY2024047)
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