Zhou Xunzhu, Zhang Qiu, Zhu Zhuo, Cai Yichao, Li Haixia, Li Fujun
Key Laboratory of Advanced Energy Materials Chemistry, Ministry of Education), Renewable Energy Conversion and Storage Center (RECAST), College of Chemistry, Nankai University, Tianjin, 300071, China.
Haihe Laboratory of Sustainable Chemical Transformations, Tianjin, 300192, China.
Angew Chem Int Ed Engl. 2022 Jul 25;61(30):e202205045. doi: 10.1002/anie.202205045. Epub 2022 Jun 2.
Metallic Na is a promising anode for rechargeable batteries, however, it is plagued by an unstable solid electrolyte interphase (SEI) and Na dendrites. Herein, a robust anion-derived SEI is constructed on Na anode in a high-concentration 1,2-dimethoxyethane (DME) based electrolyte with a cosolvent hydrofluoroether, which effectively restrains Na dendrite growth. The hydrofluoroether can tune the solvation configuration of the electrolyte from three-dimensional network aggregates to solvent-cation-anion clusters, enabling more anions to enter and reinforce the inner solvation sheath and their stepwise decomposition. The gradient inorganic-rich SEI leads to a reduced energy barrier of Na migration and enhanced interfacial kinetics. These render the Na||Na V (PO ) battery with an excellent rate capability of 79.9 mAh g at 24 C and a high capacity retention of 94.2 % after 6000 cycles at 2 C. This highlights the modulation of the electrode-electrolyte interphase chemistry for advanced batteries.
金属钠是一种很有前景的可充电电池负极材料，然而，它受到不稳定的固体电解质界面（SEI）和钠枝晶的困扰。在此，通过在基于1,2-二甲氧基乙烷（DME）的高浓度电解质中加入共溶剂氢氟醚，在钠负极上构建了一种坚固的阴离子衍生SEI，有效抑制了钠枝晶的生长。氢氟醚可以将电解质的溶剂化构型从三维网络聚集体调整为溶剂-阳离子-阴离子簇，使更多阴离子进入并强化内溶剂化鞘层及其逐步分解。富含无机成分的梯度SEI降低了钠迁移的能垒并增强了界面动力学。这些使得Na||Na V(PO)电池在24℃时具有79.9 mAh g的优异倍率性能，在2C下循环6000次后仍具有94.2%的高容量保持率。这突出了通过调控电极-电解质界面化学来制备先进电池的重要性。
