离子
振荡(细胞信号)
钠
电压
物理
材料科学
化学
电气工程
工程类
生物化学
冶金
量子力学
作者
Lan‐Fang Que,Fu‐Da Yu,Jihuai Wu,Zhang Lan,Yu Feng,Ruizheng Zhao,Zhihao Sun,Zhuo Yang,Hao Luo,Dongliang Chao
标识
DOI:10.1073/pnas.2311075121
摘要
Voltage oscillation at subzero in sodium-ion batteries (SIBs) has been a common but overlooked scenario, almost yet to be understood. For example, the phenomenon seriously deteriorates the performance of Na 3 V 2 (PO 4 ) 3 (NVP) cathode in PC (propylene carbonate)/EC (ethylene carbonate)-based electrolyte at −20 °C. Here, the correlation between voltage oscillation, structural evolution, and electrolytes has been revealed based on theoretical calculations, in-/ex-situ techniques, and cross-experiments. It is found that the local phase transition of the Na 3 V 2 (PO 4 ) 3 (NVP) cathode in PC/EC-based electrolyte at −20 °C should be responsible for the oscillatory phenomenon. Furthermore, the low exchange current density originating from the high desolvation energy barrier in NVP-PC/EC system also aggravates the local phase transformation, resulting in severe voltage oscillation. By introducing the diglyme solvent with lower Na-solvent binding energy, the voltage oscillation of the NVP can be eliminated effectively at subzero. As a result, the high capacity retentions of 98.3% at −20 °C and 75.3% at −40 °C are achieved. The finding provides insight into the abnormal SIBs degradation and brings the voltage oscillation behavior of rechargeable batteries into the limelight.
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