由于全球日益突出的能源问题和环境问题，锂离子电池作为一种新能源，具有高容量、长寿命等优势被广泛应用在智能手机、手提电脑、电动汽车及储能电站等领域。然而，由于商用有机碳酸酯类电解液中存在漏液、易燃等安全性问题严重制约了锂离子电池的进一步发展。因此，开发新型安全性电解质已成为锂电池研究领域的热点。离子液体作为一种“绿色溶剂”，具有高热稳定性、高电化学稳定性以及不可燃性等特点，因而近年来作为二次电池新型电解液材料研究的重要方向而得到科研人员的广泛关注。本文通过合成不同结构的新型离子液体，经复合高浓度锂盐、不可燃的氮化硼及聚合物，研究制备了一系列具有高安全特性的新型电解质材料，并从结构、组成、物化特性、电化学稳定性、材料兼容性以及高温匹配性等方面对新型离子液体基电解质材料进行了系统的研究，具体内容如下： (1)高浓度锂盐LiTFSI的离子液体电解质。首次将高浓度LiTFSI溶解在FSI-基离子液体Pyr〓FSI中。离子液体Pyr〓FSI粘度较低，但热稳定较差。LiTFSI的加入提高了Pyr〓FSI的热稳定性，同时进一步扩宽了该类电解质的电化学窗口。研究表明，高浓度离子液体电解质与锂金属有良好的电化学稳定性，可以有效地抑制锂枝晶的生长和锂金属负极的腐蚀；基于两种阴离子TFSI⁻和FSI⁻的协同作用，锂金属表面的SEI膜中含有大量TFSI⁻阴离子，显著提高了锂离子的嵌入/剥离的可逆性；该类高浓度电解质对高压正极材料具有良好的电化学兼容性，适用于4.4VLiCoO₂/Li高压电池，该电池在高温下表现出优异的循环稳定性和高倍率性能。 (2)高能球磨法制备纳米BN基离子凝胶电解质。利用高能球磨法制备了nanoBN复合离子液体的固态离子凝胶电解质，在高能球磨的作用下，离子液体电解质有效复合到nanoBN颗粒形成的骨架中。与常规液态离子液体电解质相比，nanoBN基离子凝胶电解质可以有效提高电解质与锂金属的稳定性：当nanoBN与离子液体电解质的质量比为1:1时，制备出的离子凝胶电解质nanoBN-ILE11具备最优电化学性能； nanoBN-ILE11电解质组装成的Li₄Ti₅O₁₂/Li固态电池在60℃时0.2C倍率下循环400周的放电比容量高达147.8mAhg⁻¹。 (3)可柔性化的BN基固态化电解质。针对固态化电解质存在的高压电化学稳定性差的缺点，选用具备高比表面积的microBN颗粒，与离子液体复合研究得到柔性化microBN基固态化电解质。当microBN与离子液体电解质的质量比为1:1时，固态化离子凝胶电解质样品microBN-ILE11表现出最优的电化学性能、机械性能和柔性特征。匹配microBN-ILE11电解质的固态电池在高温时表现出稳定的循环性能以及良好的倍率性能；组装到高温LiFePO₄/Li电池中，经过300次充放电循环后，0.1C时放电比容量高达128.7mAh g⁻¹；组装的Li₄Ti₅O₁₂/Li固态电池，在0.2C电流密度下循环400周的放电比容量为155.3mAh g⁻¹，库伦效率高达99.9%。 (4)高热稳定性的固态聚合物离子凝胶电解质膜。基于BN较高的热稳定性，采用溶剂法成功制备出以BN和PVDF-HFP为骨架的柔性固态离子凝胶电解质膜，以离子液体为基，在保证电解质膜具有高离子电导率的基础上，有效提高其安全性和机械强度。通过调节BN和PVDF-HFP的配比，搭建稳定的多孔网络结构，通过分子间作用力等配位作用实现离子液体在孔结构中的均匀分散，提高了电解质膜的离子电导率。匹配P-BN-ILE固态电解质膜的锂金属电池在室温和高温100℃、120℃下表现出良好的循环稳定性、电化学可逆性和倍率性能。 关键词：离子液体；电解质；锂离子电池；氮化硼，安全性；应用

 Due to the increasingly prominent global energy and environmental problems, lithium-ion batteries as a new energy, are widely used in smart phones, laptop computers, electric vehicles and energy storage power stations. However, because of the safety concerns including leakage and flammability in the commercial electrolyte, the further development of lithium ion batteries is severely dogged. Therefore, developing new kinds of safe electrolytes has become a hot spot in the field of lithium batteries research. As a "green solvent", ionic liquids are used as electrolytes in lithium ion battery due to their non-flammability, high thermal and electrochemical stability. Based on ionic liquids, a series of high-safety electrolytes were prepared by combining high-concentration lithium salts, nonflammable boron nitride and polymers. The structure, composition, physicochemical properties, material compatibility, high temperature matching and electrochemical stability of the prepared electrolytes were systematically studied. The details are as follows: (1)The ionic liquid electrolyte containing high concentration lithium salt LiTFSI. For the first time, high concentration LiTFSI was dissolved in FSI-based ionic liquids Pyr〓FSI. The ionic liquids Pyr〓FSI had low viscosity but poor thermal stability. The addition of LiTFSI not only improves the thermal stability of Pyr〓FSI, but also further stabilizes the electrochemical window of the electrolyte. High concentrated ionic liquid electrolyte has good electrochemical stability with lithium metal, which effectively inhibits the growth of Li dendrite and corrosion of Li metal anode. Due to the synergistic effect of TFSI⁻ and FSI⁻ anions, a stable SEI layer containing a large number of TFSI⁻ anions was formed on the surface of lithium metal, which significantly improved the reversibility of lithium ion deposition/stripping. Lithium metal batteries with a high concentration ionic liquid electrolyte have good compatibility with different electrode materials. Especially, high concentration electrolyte was used in a 4.4 V LiCoO₂/Li high voltage battery, which showed excellent cycle stability and high rate performance at high temperature. (2)Ionic gel electrolytes based nanoBN prepared by high-energy ball milling. In this chapter, solid state ionic gel electrolytes combined with nanoBN and ionic liquids were successfully prepared by high-energy ball milling. Under the action of high-energy ball milling, ionic liquid electrolytes can be fdled into the skeleton formed by nanoBN particles, providing a fast path for lithium ion migration. Infrared spectra show that BN nanoparticles can be successfully combined with liquid electrolyte without chemical reactions within the molecular structure. Compared with the conventional liquid ionic liquid electrolyte, ionic gel electrolyte based nanoBN can effectively improve the stability of electrolyte and lithium metal. When the mass ratio of nanoBN to ionic liquid electrolyte is 1:1, the ionic gel electrolyte has the best comprehensive performance. The specific discharge capacity of Li₄Ti₅O₁₂/Li solid-state battery assembled by nanoBN-ILE11 electrolyte is as high as 147.8 mAh g⁻¹after 400 cycles under 0.2 C current density at 60 ℃. (3)Flexible solid state electrolytes based microBN. In order to overcome the defects of high voltage electrochemical stability of solid electrolyte in the previous chapter, BN micropaticles with high specific surface area were selected to form a flexible solid ionic gel electrolyte with ionic liquid. When the mass ratio of microBN to ionic liquid electrolyte is 1:1, the solid state electrolyte has the excellent electrochemical, mechanical and flexible properties. Solid state batteries matching microBN-ILEll electrolyte exhibit stable cycle performance and good rate performance at high temperatures. microBN-ILEll electrolyte can be used in high temperature LiFePO₄/Li batteries. At different rates, after 300 charge and discharge cycles, the discharge capacity at 0.1 C is as high as 128.7 mAh g⁻¹. The assembled Li₄Ti₅O₁₂/Li solid state battery has a discharge specific capacity of 155.3 mAh g⁻¹ at a current density of 0.2 C for 400 cycles, and the capacity retention rate is as high as 99.9 %. (4)A thermally stable solid state polymer ionic gel electrolyte membrane. Based on the high thermal stability of boron nitride, a flexible solid state polymer ionic gel electrolyte membrane with BN and PVDF-HFP as the backbone was successfully prepared by solvent method. The membrane was based on ionic liquids. On the premise of ensuring the high ionic conductivity of the electrolyte membrane, it was endowed with high safety and high mechanical strength. By adjusting the proportion of boron nitride and PVDF-HFP, a solid porous network structure was constructed, and the ionic liquids were evenly dispersed into the pore size to improve the ionic conductivity of the electrolyte membrane. Lithium-metal batteries with P-BN-ILE solid-state electrolyte film have good cycle stability, electrochemical reversibility and rate performance at room temperature and high temperature of 100 ℃ and 120 ℃. Key Words: ionic liquid; electrolytes; lithium ion battery; BN; safety; application