【作者】 李慧；

【导师】 陈万煜； 马双平；

【作者基本信息】 武汉理工大学 ， 材料工程（专业学位）， 2024， 硕士

【摘要】 目前化石燃料存在大量消耗和环境污染的问题,人们对开发新型储能系统的需求也日渐增大。水性锌离子电池因其低成本、固有安全性和环保性等优点,被认为是一种非常有前景的储能技术。现在对水性锌离子电池中电解质的研究和改进多集中在正极、负极和电解质方面。亟需开发一种用于锌离子电池的凝胶电解质,在环保的同时抑制锌离子电池中由水引起的各种问题,并且在保证电解质电导率的同时扩大电池可使用温区。本研究中利用L-亮氨醇、甲苯和草酸二乙酯合成了一种小分子凝胶因子（BLO）,并由1-乙基-3-甲基咪唑四氟硼酸盐（EMIMBF₄）离子液体与四氟硼酸锌（Zn（BF₄）₂）制备了离子液体电解质（ILZE）。将凝胶因子溶于离子液体电解质中,凝胶因子在凝胶化温度以下通过氢键自组装形成一种新颖的离子液体超分子凝胶电解质（记为BLO-ILZE电解质）。该体系最显著的优点是减少了锌的枝状镀锌/脱镀反应,有效抑制了析氢反应和副反应,并且在操作简便的同时拓宽了电解质的可使用温度区间（-70～100℃）。结果表明,在较宽的温度范围内,超分子凝胶电解质能显著提高电导率并满足液态定律（-70～100℃）,在-40℃下能达到2.12 mS cm^-1的高电导率。而水性锌离子电池（Zn SO₄/H₂O）在-10℃下的电导率为2.33mS cm^-1。与离子液体电解质和Zn（BF₄）₂水溶液电解质相比,加入超分子凝胶电解质的Zn|Zn对称电池具有更好的循环稳定性,表明对锌枝晶有显著的抑制作用。利用SEM、EDS、XRD和激光显微镜对稳定性提高的原因进行测试和分析,结果表明采用超分子凝胶电解质的对称电池的循环时间是水性锌离子电池的8.5倍。通过电化学阻抗测试对超分子凝胶电解质在不同温度下的离子电导率进行了研究。对使用超分子凝胶电解质作为电解质的Zn|Zn对称电池的镀锌/脱镀长期循环稳定性进行了研究,发现与含有Zn（BF₄）₂溶液的水性锌离子电池(在1 mA cm^-2下400 h)相比,超分子凝胶电解质能有效抑制析氢反应从而使Zn|Zn电池在1 mA cm^-2下的寿命延长到3470 h。使用超分子凝胶电解质组装了Zn|Cu半电池并研究了其长期库伦效率,组装了Zn|V₂O₅全电池,对它们包括倍率性能,长期循环稳定性和循环伏安测试的电化学性能进行了测试。研究发现V₂O₅/BLO-ILZE/Zn全电池表现出好的循环性能,在0.5mA g^-1的电流密度下可以循环5000次,容量为98%,库仑效率为100%。更多还原

【Abstract】 At present,there are large consumption of fossil fuels and environmental pollution problems,and people’s demand for the development of new energy storage systems is also increasing.Aqueous zinc-ion batteries are considered as a promising energy storage technology because of their low cost,inherent safety and environmental protection.At present,the research and improvement of electrolytes in aqueous zinc ion batteries mainly focus on the positive electrode,the negative electrode and the electrolyte.There is an urgent need to develop a gel electrolyte for zinc-ion batteries,which can inhibit various problems caused by water in zinc-ion batteries while protecting the environment,and expand the battery’s usable temperature range while ensuring the electrolyte conductivity.In this study,a gel factor（BLO）was synthesized from L-leucomanol,toluene and diethyl oxalate,and an ionic liquid electrolyte（ILZE）was prepared from 1-ethyl-3-methylimidazolium tetrafluoroborate（EMIMBF₄）ionic liquid and zinc tetrafluoroborate（Zn（BF₄）₂）.The BLO gel factor was dissolved in the ILZE electrolyte,and the gel factor self-assembled by hydrogen bonding below the gelation temperature to form a novel ionic liquid supramolecular gel electrolyte（denoted as BLO-ILZE electrolyte）.The most significant advantages of this system are the reduction of branch plating/stripping reaction of zinc,the reduction of hydrogen evolution reaction and side reactions,the easy operation,and the widening of the usable temperature range of the electrolyte（-70～100℃）.The results show that BLO-ILZE can significantly improve the conductivity and satisfy the liquid state law（-70 to 100℃）over a wide temperature range,and achieve high conductivity(2.12 mS cm^-1)at-40℃.The conductivity of the aqueous zinc-ion battery（Zn SO₄/H₂O）at-10℃is 2.33mS cm^-1.Compared with ILZE electrolyte and Zn（BF₄）₂ aqueous electrolyte,the Zn||Zn symmetrical cell with BLO-ILZE supramolecular gel electrolyte showed better cycling stability,indicating a significant inhibition of zinc dendrites.The reasons for the improved stability were tested and analyzed using SEM,EDS,XRD,and laser microscopy,and the results showed that the cycle time of the symmetrical cell with supramolecular gel electrolyte was 8.5 times that of the aqueous ZIBs.The ionic conductivity of BLO-ILZE supramolecular gel electrolyte at different temperatures was investigated by electrochemical impedance testing.The use of BLO-ILZE as electrolyte Zn||Zn symmetric battery zinc galvanized/plating off cycle stability is studied for a long time.Compared with aqueous ZIBs containing Zn（BF₄）₂ solution(400 h at 1 mA cm^-2),BLO-ILZE effectively inhibited the hydrogen evolution reaction,thereby extending the lifetime of Zn||Zn cells to 3470 h at 1 mA cm^-2.Using the BLO-ILZE the supramolecular assembly gel electrolyte Zn||Cu half cell and study its long-term coulomb efficiency,assemble the Zn||V₂O₅ full battery,they include ratio performance,long cycle stability test and cyclic voltammograms of the electrochemical properties were tested.The V₂O₅/BLO-ILZE/Zn whole cell also showed good cycling performance,with a capacity of 98%and a Coulomb efficiency of 100%for 5000cycles at the current density of 0.5mA g^-1.更多还原