开发KPF6 / KFSA二元盐解决方案，用于长寿命和高压钾离子电池。,ACS Applied Materials & Interfaces

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开发KPF6 / KFSA二元盐解决方案，用于长寿命和高压钾离子电池。
ACS Applied Materials & Interfaces ( IF 8.3 ) Pub Date : 2020-07-22 , DOI: 10.1021/acsami.0c08002
Tomooki Hosaka ₁ , Tatsuo Matsuyama ₁ , Kei Kubota _{1,

2} , Satoshi Yasuno ₃ , Shinichi Komaba _{1,

2}

Affiliation

通过阐明盐分比和不同溶剂对物理性能的影响，开发了一系列在碳酸酯溶剂中的KPF ₆ / KN（SO ₂ F）₂（KFSA）二元盐电解质电解质溶液和K离子电池的电化学性能 KPF ₆ / KFSA碳酸酯溶液（例如KPF ₆ / KFSA碳酸亚乙酯（EC）/碳酸二乙酯（DEC））显示出比单盐KPF ₆ one更高的离子电导率，更高的KFSA含量导致更高的离子电导率。含有KPF ₆的富含KPF _6的二元盐电解质/ KFSA比值≥3（mol / mol）可提供足够的氧化稳定性和钝化性能，在4.6 V电压下100小时内可抵抗Al腐蚀，确保4 V级正极K ₂ Mn [Fe（CN）₆ ]的一半可逆运行-细胞。石墨负极在0.75 mol kg ^–1 K（PF ₆）_0.9（FSA）_0.1 / EC / DEC和1 mol kg ^–1 K（PF ₆）_0.75（FSA）_0.25 / EC /时表现出更高的库仑效率和更好的倍率性能。DEC电解质要比KPF _6中的一种。硬X射线光电子能谱的表面分析表明N（SO ₂F）₂^–阴离子有助于稳定石墨电极上的固体电解质相间。通过比较EC / DEC，EC /碳酸乙基甲基酯和EC /碳酸亚丙酯（PC）的不同溶剂，K ₂ Mn [Fe（CN）₆ ]电极在EC / PC二元电解质中显示出最高的库仑效率，而石墨电极没有显着差异。在半电池测试的基础上，我们成功实现了3.6 V级充满石墨的石墨| K（PF ₆）_0.75（FSA）_0.25 / EC / PC | K ₂ Mn [Fe（CN）₆ ]在500之上显示出优异的循环性能循环，远远优于传统的KPF ₆/ EC / DEC电解质电池。

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Development of KPF6/KFSA Binary-Salt Solutions for Long-Life and High-Voltage K-Ion Batteries.

A series of binary-salt electrolytes of KPF₆/KN(SO₂F)₂ (KFSA) in carbonate ester solvents have been developed for high-voltage K-ion batteries by clarifying the effect of salt ratio and different solvents on the physical properties of the electrolyte solutions and electrochemical performance of K-ion batteries. The KPF₆/KFSA carbonate ester solutions, such as KPF₆/KFSA ethylene carbonate (EC)/diethyl carbonate (DEC), exhibit higher ionic conductivity than single-salt KPF₆ one, and higher KFSA content results in higher ionic conductivity. The KPF₆-rich binary-salt electrolytes with KPF₆/KFSA ratios of ≥3 (mol/mol) provide enough oxidation stability and passivation against Al corrosion at 4.6 V over 100 h, ensuring reversible operation of a 4 V class positive electrode, K₂Mn[Fe(CN)₆] in half-cell. Graphite negative electrodes exhibit higher Coulombic efficiency and better rate performance in 0.75 mol kg^–1 K(PF₆)_0.9(FSA)_0.1/EC/DEC and 1 mol kg^–1 K(PF₆)_0.75(FSA)_0.25/EC/DEC electrolytes than those in the KPF₆ one. Surface analysis by hard X-ray photoelectron spectroscopy reveals that the decomposition product of N(SO₂F)₂^– anion contributes to stabilizing solid electrolyte interphase on a graphite electrode. From comparing different solvents of EC/DEC, EC/ethyl methyl carbonate, and EC/propylene carbonate (PC), the K₂Mn[Fe(CN)₆] electrode demonstrates the highest Coulombic efficiency in the EC/PC binary electrolyte, while graphite electrodes exhibit no significant difference. Based on the half-cell tests, we successfully achieve the 3.6 V class full cell of graphite|K(PF₆)_0.75(FSA)_0.25/EC/PC|K₂Mn[Fe(CN)₆] showing excellent cyclability over 500 cycles, which is far superior to that of the conventional KPF₆/EC/DEC electrolyte cell.

更新日期：2020-08-05

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