Solid electrolytes are the most promising candidate for replacing liquid electrolytes due to their safety and chemical stability advantages. However, a single inorganic or organic solid electrolyte cannot meet the requirements of commercial all-solid-state batteries (ASSBs), which motivates the composite polymer electrolyte (CPE). Herein, a CPE of boron nitride nanofiber (BNNF) with a high specific surface area, rich pore structure, and poly (ethylene oxide) (PEO) are reported. Anions strongly adsorb on the surface of BNNF through electrostatic interactions based on oxygen vacancies, promoting the dissociation of lithium salts at the two-phase interface. The three-dimensional (3D) BNNF network provides three advantages in the CPE, including (i) improving ionic conductivity through strong interaction between polymers and fillers, (ii) improving mechanical properties through weaving a robust skeleton, and (iii) improving stability through a rapid and uniform thermal dispersion pathway. Therefore, the CPE with BNNF delivers high ionic conduction of 4.21 × 10−4 S cm−1 at 60 °C and excellent cycling stability (plating/stripping cycles for 2000 h with a low overpotential of ∼40 mV), which results in excellent electrochemical performance of LiFePO4 (LFP) full cell assembled with CPE-5BNNF-1300 (152.7 mAh g−1 after 200 cycles at 0.5 C, and 134.8 mAh g−1 at 2.0 C). Furthermore, when matched with high-voltage LiNi0.6Co0.2Mn0.2O2 (NCM622), it also exhibits an outstanding rate capacity of 120.4 mAh g−1 at 1.0 C. This work provides insight into the BNNF composite electrolyte and promotes its practical application for ASSBs.

中文翻译：

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富含氧空位的高比表面积活性氮化硼纳米纤维增强了全固态复合电解质的界面稳定性


固体电解质因其安全性和化学稳定性优势而成为替代液体电解质的最有希望的候选者。然而，单一的无机或有机固体电解质无法满足商用全固态电池 （ASSB） 的要求，这激发了复合聚合物电解质 （CPE） 的开发。本文报道了一种具有高比表面积、丰富孔隙结构和聚环氧乙烷 （PEO） 的氮化硼纳米纤维 （BNNF） 的 CPE。阴离子通过基于氧空位的静电相互作用强烈吸附在 BNNF 表面，促进锂盐在两相界面处的解离。三维 （3D） BNNF 网络在 CPE 中提供了三个优势，包括 （i） 通过聚合物和填料之间的强烈相互作用提高离子电导率，（ii） 通过编织坚固的骨架来改善机械性能，以及 （iii） 通过快速均匀的热分散途径提高稳定性。因此，带有 BNNF 的 CPE 在 60 °C 时提供 4.21 × 10-4 S cm-1 的高离子传导和出色的循环稳定性（电镀/剥离循环 2000 小时，低过电位 ∼40 mV），这导致与 CPE-5BNNF-1300 组装的 LiFePO4 （LFP） 全电池具有出色的电化学性能（在 0.5 C 下循环 200 次后为 152.7 mAh g-1， 和 134.8 mAh g-1 在 2.0 C 下）。此外，当与高压 LiNi0.6Co0.2Mn0.2O2 （NCM622） 匹配时，它还在 1.0 C 时表现出 120.4 mAh g-1 的出色倍率容量。这项工作为了解 BNNF 复合电解质提供了见解，并促进了其在 ASSB 中的实际应用。