As a promising anode material, silicon has attracted extensive attention. The instability of the electrode/electrolyte interphase due to the inherent volume variation upon (de)lithiation is one of the major factors limiting the commercialization of silicon anode materials. Here, we report a concentrated electrolyte with lithium bis(fluorosulfonyl)imide (LiFSI) and lithium difluoro (oxalate) borate (LiDFOB) dual salt to enhance the control of the species constituting the solid electrolyte interphase (SEI) on the surface of the silicon material. The silicon nanoparticle (SiNP) electrode with the dual‐salt LiFSI_0.7LiDFOB_0.3‐(PC)₄ concentrated electrolyte delivers a relatively high average coulombic efficiency of 97.68 % and a remarkably improved cycling performance with an initial capacity of approximately 3300 mAh g⁻¹ and a capacity retention around 2000 mAh g⁻¹ after 100 cycles. It is found that the polarity of the B−F bond of LiDFOB decreases when the molar ratio of LiDFOB to LiFSI is greater than 0.3 : 0.7. Therefore, the reduction of LiDFOB through a ring‐opening reaction coupled with a ring‐opening reaction of PC becomes dominant. The SEI layer rich in the corresponding products Li(BF₂O)_n polymer could suppress the rupture of the Si particles and excessive growth of the SEI layer, thus could further mitigate the decrease of coulombic efficiency.

中文翻译：

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双盐浓缩电解质对硅纳米粒子电化学性能的影响

作为有前途的阳极材料，硅已经引起了广泛的关注。由于（去）锂化时固有的体积变化而导致的电极/电解质中间相的不稳定性是限制硅阳极材料的商业化的主要因素之一。在这里，我们报告了一种浓缩电解质，其中含有双（氟磺酰基）酰亚胺锂（LiFSI）和二氟（草酸）硼酸锂（LiDFOB）双盐，以增强对构成硅表面上固体电解质中间相（SEI）的物质的控制。材料。具有双盐LiFSI _0.7 LiDFOB _0.3-（PC）₄的硅纳米粒子（SiNP）电极浓缩电解质提供了相对较高的平均库仑效率97.68％和显着改善的循环性能，其初始容量约为3300 mAh g ^-1，在100次循环后的容量保持率约为2000 mAh g ^-1。发现当LiDFOB与LiFSI的摩尔比大于0.3∶0.7时，LiDFOB的BF键的极性降低。因此，通过PC的开环反应和PC的开环反应还原LiDFOB成为主流。富含相应产物Li（BF ₂ O）_n的SEI层可以抑制Si颗粒的破裂和SEI层的过度生长，从而可以进一步缓解库仑效率的降低。