Hao Zhiqiang, Shi Xiaoyan, Zhu Wenqing, Yang Zhuo, Zhou Xunzhu, Wang Chenchen, Li Lin, Hua Weibo, Ma Chang-Qi, Chou Shulei
Institute for Carbon Neutralization, College of Chemistry and Materials Engineering, Wenzhou University, Wenzhou, Zhejiang 325035, People's Republic of China.
Wenzhou Key Laboratory of Sodium-Ion Batteries, Wenzhou University Technology Innovation Institute for Carbon Neutralization, Wenzhou, Zhejiang 325035, People's Republic of China.
ACS Nano. 2024 Apr 2;18(13):9354-9364. doi: 10.1021/acsnano.3c09519. Epub 2024 Mar 22.
NaV(PO) (NVP) based on the multielectron reactions between V and V has been considered a promising cathode for sodium-ion batteries (SIBs). However, it still suffers from unsatisfactory stability, caused by the poor reversibility of the V/V redox couple and structure evolution. Herein, we propos a strategy that combines high-entropy substitution and electrolyte optimization to boost the reversible multielectron reactions of NVP. The high reversibility of the V/V redox couple and crystalline structure evolution are disclosed by X-ray absorption near-edge structure spectra and X-ray diffraction. Meanwhile, the electrochemical reaction kinetics of high-entropy substitution NVP (HE-NVP) can be further improved in the diglyme-based electrolyte. These enable HE-NVP to deliver a superior electrochemical performance (capacity retention of 93.1% after 2000 cycles; a large reversible capacity of 120 mAh g even at 5.0 A g). Besides, the long cycle life and high power density of the HE-NVP∥natural graphite full-cell configuration demonstrated the superiority of HE-NVP cathode in SIBs. This work highlights that the synergism of high-entropy substitution and electrolyte optimization is a powerful strategy to enhance the sodium-storage performance of polyanionic cathodes for SIBs.
基于V和V之间多电子反应的NaV(PO) (NVP)被认为是一种有前景的钠离子电池（SIBs）正极材料。然而，由于V/V氧化还原对的可逆性差和结构演变，它仍然存在稳定性不理想的问题。在此，我们提出一种将高熵取代和电解质优化相结合的策略，以促进NVP的可逆多电子反应。通过X射线吸收近边结构光谱和X射线衍射揭示了V/V氧化还原对的高可逆性和晶体结构演变。同时，在基于二甘醇二甲醚的电解质中，高熵取代NVP（HE-NVP）的电化学反应动力学可以进一步改善。这些使得HE-NVP能够展现出优异的电化学性能（2000次循环后容量保持率为93.1%；即使在5.0 A g的电流密度下也具有120 mAh g的大可逆容量）。此外，HE-NVP∥天然石墨全电池配置的长循环寿命和高功率密度证明了HE-NVP正极在SIBs中的优越性。这项工作突出了高熵取代和电解质优化的协同作用是提高SIBs聚阴离子正极储钠性能的有力策略。
