A high-concentrated and nonflammable electrolyte for potassium ion-based dual-graphite batteries
A high-concentrated and nonflammable electrolyte for potassium ion-based dual-graphite batteries
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DOI：
10.1007/s12274-023-5438-z
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发表时间：
2023-01-16
期刊：
影响因子：
9.9
通讯作者：
Chen, Da
中科院分区：
文献类型：
--
作者：
Li, Kexin;Ma, Guiyou;Chen, Da
基于钾离子的双石墨电池（KDGB）由于其高电压、低成本和环境友好性而成为具有大规模应用前景的设备。然而，传统的KPF 6/碳酸盐基电解质遭受严重的氧化分解、低浓度和易燃性，这限制了KDGB的容量和循环能力。本文设计了一种用于KDGB的不易燃的双（氟磺酰基）酰亚胺钾/磷酸三乙酯（KFSI/TEP）电解液。当盐与溶剂的摩尔比增加到1：1.3时，在5.2V的截止电位下操作的石墨阴极表现出显著提高的容量、优异的倍率性能（在1.0A·g（-1）下为26.4mAh·g（-1））和上级的循环性能，在350次循环后容量保持率为98%。源自FSI-阴离子优先分解的富含无机化合物的电极/电解质界面层确保了1：1.3 KFSI/TEP电解质与K金属和石墨阳极的良好相容性。基于该电解液组装的KDGB具有4.3V的工作电压和良好的循环性能.为研制长寿命、安全运行的DGB提供了可行性。
Potassium ion-based dual-graphite batteries (KDGBs) emerge as promising devices for large-scale applications due to their high voltage, low cost, and environmental friendliness. However, conventional KPF6/carbonate-based electrolytes suffer from severe oxidation decomposition, low concentration, and flammability, which limit the capacity and cyclability of KDGBs. Herein, a nonflammable potassium bis(fluorosulfonyl)imide/triethyl phosphate (KFSI/TEP) electrolyte was designed for KDGBs. When the salt-to-solvent molar ratio increases to 1:1.3, graphite cathode operated at the cut-off potential of 5.2 V exhibits much enhanced capacity, excellent rate capability (26.4 mAh.g(-1) at 1.0 A.g(-1)), and superior cyclability with 98% capacity retention after 350 cycles. Inorganic compounds-rich electrode/electrolyte interphase layers derived from the preferential decomposition of FSI- anions ensure good compatibility of the 1:1.3 KFSI/TEP electrolyte with K metal and graphite anodes. Based on this electrolyte, asassembled KDGBs show high operation voltage of 4.3 V and good cycling performance. This work provides feasibility for developing long-life and safe-operation DGBs.