目的 以羧甲基纤维素钠(CMC)和聚丙烯酸(PAA)为原料制备气凝胶型钠离子电池隔膜，探究交联温度对其孔结构的影响，实现隔膜的电化学性能超过玻璃纤维。方法 用溶胶凝胶法结合冷冻干燥法制备CMC-PAA的气凝胶薄片，辅以高温交联稳固其孔结构，通过微观测试和力学性能表征探究了温度对其影响，并与玻璃纤维对比其组装在钠离子半电池中的充放电比容量数据。结果 随着交联温度的升高，隔膜中PAA的羧基与CMC的羟基的交联度增加，因此，隔膜的孔径和孔隙率略有减小；隔膜的断裂伸长率出现先增加后减小的现象。CMC︰PAA质量比为1︰1、交联温度为130 ℃条件下制备的气凝胶型隔膜组装后，钠离子电池在25、50、100、250、500、1 000和25 mA/g电流密度的充放电速率下，充电比容量分别表现为345.8、317.3、274.2、136.8、84.8、61.8和341.4 mA·h/g，均优于在相同条件下的玻璃纤维(279.0、233.1、190.5、105.9、69.6、49.4和275.1 mA·h/g)。130 ℃-CMC-PAA因其较小的电解液泄露率，使其以1.877 mS/cm的离子电导率和5.52 Ω的电阻，高于传统商用聚烯烃类隔膜表现出的电化学性能。结论 以CMC和PAA这2种水溶性材料在130 ℃下交联制备的电池隔膜的电化学性能超过玻璃纤维，其在钠离子电池应用中具有良好的前景。
Objective The aerogel sodium ion battery separator with electrochemical performance exceeding that of glass fiber was prepared using carboxy methyl cellulose sodium (CMC) and polyacrylic acid (PAA) as raw materials, and the effect of cross-linking temperature on pore structure of the separator was explored to realize the electrochemistry performance exceeding that of glass fibre.Method The sol-gel method and freeze-drying method were used to prepare CMC-PAA aerogel sheets, supplemented by high temperature cross-linking to stabilize the pore structure. The influence of temperature on the diaphragm was explored through microscopic testing and mechanical performance characterization. The charge-discharge specific capacities of sodium ion half cell with separators of CMC-PAA and glass fibre were compared.Result With the increase of cross-linking temperature, the cross-linking degree of the carboxyl group of PAA and the hydroxyl group of CMC in the diaphragm increased. As a result, the pore size and porosity of the diaphragm slightly decreased; The elongation at break of the separator appeared to first increase and then to decrease. When the aerogel battery separator was prepared with a mass ratio of CMC︰PAA=1︰1 and a cross-linking temperature of 130 ℃, the charge-discharge specific capacity of the sodium ion battery exhibited 345.8, 317.3, 274.2, 136.8, 84.8, 61.8 and 341.4 mA·h/g at charge-discharge rates of 25, 50, 100, 250, 500, 1 000 and 25 mA/g current densities, showing better properties than those of glass fibres (279.0, 233.1, 190.5, 105.9, 69.6, 49.4, and 275.1 mA·h/g) under the same conditions. 130 ℃-CMC-PAA exhibited a much higher electrochemistry performance than conventional commercial polyolefin diaphragms due to its smaller electrolyte leakage rate, which resulted in an ionic conductivity of 1.877 mS/cm and a resistance of 5.52 Ω. Conclusion The application of battery separators made of two water-soluble materials of CMC and PAA under 130 ℃ cross-linking in sodium ion batteries has good potentials, having better electrochemistry performance than glass fiber.