As a promising cathode material for high-performance lithium-ion batteries, olivine LiFe_1-xMn_xPO₄ (0 < x < 1, LFMP) combines the high safety of LiFePO₄ and the high energy density of LiMnPO₄. During the charge-discharge process, poor interface stability of active materials leads to capacity decay, which prevents its commercial application. Here, to stabilize the interface, a new electrolyte additive potassium 2-thienyl tri-fluoroborate (2-TFBP) is developed to boost the performance of LiFe_0.3Mn_0.7PO₄ at 4.5 V vs. Li/Li⁺. Specifically, after 200 cycles, the capacity retention remains at 83.78% in the electrolyte containing 0.2% 2-TFBP while the capacity retention without 2-TFBP addition is only 53.94%. Based on the comprehensive measurements results, the improved cyclic performance is attributed to that 2-TFBP has a higher highest occupied molecular orbit (HOMO) energy and its thiophene group can be electropolymerized above 4.4 V vs. Li/Li⁺ for generating uniform cathode electrolyte interphase (CEI) with poly-thiophene, which can stable materials structure and suppress the decomposition of electrolytes. Meanwhile, 2-TFBP both promotes the deposition/exfoliation of Li⁺ at anode-electrolyte interfaces and regulates Li deposition by K⁺ cations through the electrostatic mechanism. This work presents that 2-TFBP has a great application prospect as a functional additive for high-voltage and high-energy-density lithium metal batteries.

_{橄榄石LiFe 1-x} Mn _x PO ₄ (0 < x < 1, LFMP)作为一种很有前途的高性能锂离子电池正极材料，结合了LiFePO ₄的高安全性和LiMnPO ₄的高能量密度。在充放电过程中，活性物质界面稳定性差导致容量衰减，阻碍了其商业化应用。_{在这里，为了稳定界面，开发了一种新的电解质添加剂 2-噻吩基三氟硼酸钾 (2-TFBP)，以提高 LiFe 0.3} Mn _0.7 PO ₄在 4.5 V 相对于 Li/Li ⁺的性能. 具体来说，经过200次循环后，在含有0.2% 2-TFBP的电解液中容量保持率为83.78%，而没有添加2-TFBP的容量保持率仅为53.94%。基于综合测量结果，改善的循环性能归因于 2-TFBP 具有更高的最高占据分子轨道 (HOMO) 能量，其噻吩基团可以在 4.4 V 以上电聚合 vs. Li/Li + 以生成均匀的^正极电解质与聚噻吩的中间相（CEI），可以稳定材料结构并抑制电解质的分解。^{同时，2-TFBP 既促进了 Li +}在阳极-电解质界面的沉积/剥离，又通过 K ^{+调节 Li 沉积}阳离子通过静电机制。该工作表明2-TFBP作为高电压、高能量密度锂金属电池的功能添加剂具有广阔的应用前景。