材料科学
阴极
曲面重建
分析化学(期刊)
曲面(拓扑)
光电子学
物理化学
化学
几何学
数学
色谱法
作者
Jintao Li,Zhenhao Luo,Jing Wang,Songtong Zhang,Pushpendra Kumar,Xianfeng Hao,Xiayu Zhu,Wenjie Meng,Jingyi Qiu,Hai Ming
标识
DOI:10.1021/acsami.4c10160
摘要
High-voltage LiNi0.5Mn1.5O4 (LNMO) cathodes suffer from severe capacity degradation during long-term cycling due the manganese dissolution and their high operating voltage (∼4.95 V), which pose serious challenges at the surface or interface. Moreover, both traditional ion-doping and passivation layer coating are difficult to apply consistently to LNMO cathode because of their complicated procedures, especially in large-scale production. To address these issues, a strategy employing HNO3/H2O2 leaching in synergy with a sintering process at a mid-temperature of 700 °C was used to achieve selective surface reconstruction. An optimal ratio of reactants was applied to balance the capacity and the cyclic stability of the LNMO cathode. The optimized valence composition of Mn on the material surface mitigates the occurrence of Jahn–Teller distortion, accompanied by a reasonable ratio of ordered and disordered phases and the concentration of oxygen vacancies after sintering, which improves the interface behavior between the electrode and electrolyte. This method delivers a high reversible capacity of 116.5 mAh g–1 after 200 cycles at 0.5 C (1 C = 147 mAh g–1) with a capacity retention of 91.30% and 110 mAh g–1 with a remarkably high capacity retention of 86.85% after 500 cycles at 2 C. This balanced approach, utilizing the protective effects of oxidation (O22–) and the erosive action of acid (H+), is proposed to achieve regional surface reconstruction of advanced LNMO cathode. This opens up a strategy for improving oxide-based cathode materials with low cost and mass production capability, especially favoring high consistency.
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