Formulating a New Electrolyte: Synergy between Low-Polar and Non-polar Solvents in Tailoring the Solid Electrolyte Interface for the Silicon Anode
Formulating a New Electrolyte: Synergy between Low-Polar and Non-polar Solvents in Tailoring the Solid Electrolyte Interface for the Silicon Anode
复制标题
配制新型电解质：低极性和非极性溶剂之间的协同作用定制硅阳极的固体电解质界面
DOI：
10.1021/acsami.1c16827
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发表时间：
2021
影响因子：
9.5
通讯作者：
Sun Shi-Gang
中科院分区：
文献类型：
--
作者：
Pan Si-Yu;Yang Xue-Rui;Zhou Yao;Lv Chao;Deng Hao-Tian;Guo Ming-Jia;Chen Shou-Xiao;Hu Yi-Yang;Deng Li;Qiao Yu;Li Jun-Tao;Huang Ling;Yang Yong;Sun Shi-Gang
目前，锂离子电池（LIB）采用极性电解质组装；因此，生成的 SEI 层以有机物为主。其中，低极性电解液由低极性溶剂（硅酸四乙酯，TEOS）和非极性惰性屏蔽助溶剂（环己烷，CYH）配制而成；研究了锂盐的溶剂化行为。研究发现，使用这种低极性溶剂可以提高Li+溶剂化鞘中阴离子的比例，并且非极性共溶剂的存在进一步屏蔽了阳极上溶剂的还原分解。由此产生的 SEI 层相对富含 LiF，并具有 TEOS 分子分解形成的 3D 交联 Si-O 网络作为骨架，更能耐受硅体积膨胀造成的损坏。在这种低极性电解质中的基于硅纳米粒子的阳极在200次循环后可提供高达1491 mAh g-1的容量，优于商业极性电解质中的阳极。
Currently, lithium-ion batteries (LIBs) are assembled with polar electrolytes; thus, resulting SEI layers are dominated with organics. Herein, a low-polarity electrolyte is formulated with a low-polarity solvent (tetraethyl silicate, TEOS) and a non-polar inert shielding co-solvent (cyclohexane, CYH); solvation behaviors of lithium salt are investigated. The use of such a low-polarity solvent is found to improve the fraction of anions in the solvation sheath of Li+, and the presence of the non-polar co-solvent further shields the reductive decomposition of the solvent on the anode. The resulting SEI layer is relatively rich in LiF and has a 3D cross-linked Si–O network as a skeleton from the decomposition of TEOS molecules, which is more robust to tolerate the damage from the volume expansion of silicon. A Si-nanoparticle-based anode in such a low-polarity electrolyte delivers a capacity as high as 1491 mAh g–1after 200 cycles, outperforming those in the commercial polar electrolytes.