6.0 V High‐Voltage and Concentrated Electrolyte toward High Energy Density K‐Based Dual‐Graphite Battery,Advanced Energy Materials

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6.0 V High‐Voltage and Concentrated Electrolyte toward High Energy Density K‐Based Dual‐Graphite Battery
Advanced Energy Materials ( IF 24.4 ) Pub Date : 2020-09-22 , DOI: 10.1002/aenm.202002567
Xiang Li _{1,

2} , Xuewu Ou ₁ , Yongbing Tang _{1,

2,

3,

4}

Affiliation

K‐based dual‐carbon batteries (K‐DCBs) integrate the advantages, including high‐voltage, low‐cost, and environmentally friendliness of dual‐ion batteries (DIBs), and large abundance of K, thus attracting much attention in large‐scale energy storage application. However, most currently used electrolytes based on KPF₆ and carbonate solvents commonly suffer from poor oxidation potential (<4.4 V vs Li/Li⁺) and low electrolyte concentration (<1 m), which limit the cycling stability and energy density of K‐DCBs. Herein, after a matching behavior study of various electrolyte solvents with potassium salts, a concentrated electrolyte is developed by successfully dissolving 5.2 m potassium bis(fluorosulfonyl)imide into tetramethylene sulfone. This high‐concentration electrolyte exhibits advantages: 1) high oxidation potential that enhances intercalation reversibility and capacity of FSI⁻ anions; 2) improved K⁺ storage at graphite anode; 3) dramatically increased energy density of K‐DCB. A proof‐of‐concept K‐ion dual‐graphite battery based on this high‐concentration electrolyte displays a discharge capacity of 83.4 mAh g⁻¹ at 100 mA g⁻¹, and negligible capacity fading after 300 cycles. Furthermore, considering both the electrolyte and electrode materials, energy density of such K‐DCB reaches ≈130 Wh kg⁻¹, the best performance of K‐DCBs among previously reported research.

中文翻译：

面向高能量密度K型双石墨电池的6.0 V高压集中电解质

基于K的双碳电池（K-DCB）集成了优点，包括双离子电池（DIB）的高电压，低成本和环境友好性以及大量K，因此在大型K大规模储能应用。但是，目前大多数使用的基于KPF _6的电解质和碳酸盐溶剂通常都具有较弱的氧化电势（<4.4 V vs Li / Li ⁺）和低电解质浓度（<1 m），这限制了K-DCB的循环稳定性和能量密度。在此，在对各种电解质溶剂与钾盐进行匹配行为研究之后，通过将5.2 m双（氟磺酰基）酰亚胺钾成功地溶解在四亚甲基砜中来开发浓缩电解质。这种高浓度电解质表现出的优点：1）高的氧化电位FSI的增强嵌入可逆性和能力^-的阴离子; 2）改善了石墨阳极上的K ⁺存储；3）大大增加了K-DCB的能量密度。在此基础上的高浓度电解质的显示器83.4毫安g的放电容量的证明的概念K-离子双石墨电池^-1以100mA克^-1，并且300次循环后容量衰减可忽略不计。此外，考虑到电解质和电极材料，这种K-DCB的能量密度达到≈130Wh kg ^-1，这是先前报道的研究中K-DCB的最佳性能。

更新日期：2020-11-03

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