氧化铝/丙烯酸酯乳液改性聚乙烯隔膜的制备及性能

Effect of Al2O3/Acrylate Emulsion on Performance of Polyethylene Separators

摘要:

以丙烯酸酯乳液作为粘结剂，水为分散介质，利用氧化铝颗粒对锂离子电池用聚乙烯(PE)隔膜进行陶瓷改性，得到涂覆PE隔膜，并对表面张力、接触角、浸润性、吸液率、热收缩及电化学性能等进行了表征，结果表明浆料加入0.10%含氟表面活性剂，表面张力由37.0 mN/m降低至28.5 mN/m。涂覆PE隔膜对比PE隔膜，润湿性和耐热性能以及电化学性能均得到了明显改善，吸液率由 85 % 提高到 165 %，150 ℃的热收缩率从65 %降至3 %以内。200次循环，涂覆PE隔膜和PE隔膜的容量保持率分别为 90.2 %、84.7 %，不同倍率下，涂覆PE隔膜的放电比容量比PE隔膜略高，交流阻抗、伏安循环性能两者类似。

Abstract:

The coated polyethylene(PE) separators were prepared (through a direct coating process) with Al2O3 as ceramic particle, acrylate emulsion as binder and deionized water as solvent. The PE separators and coated PE separators were characterized by surface tension, contact angles testing, electrolyte wettability, electrolyte uptake, thermal resistance, as well as electrochemical testing. The results showed that the surface tension of ceramic slurry decreased from 37.0 mN/m to 28.5 mN/m as 0.10 % fluoro-containing surfactant was added. Compared with PE separators, the wettability, heat resistance and electrochemical performance of coated PE separators were improved. The electrolyte uptake of the coated PE separators increased from 85 % to 165 %, and the thermal shrinkage decreased from 65 % to 3 % at 150 ℃. The capacity retention of the PE separators were only 84.7 % in 200 cycles, while that of the coated PE separators reached 90.2 % at the same condition. The capacity retention rates of the coated PE separators were slightly higher than that of the PE separators at different charge-discharge rate. The complex impedance and cyclic voltammograms of these two materials were similar.