A cross-linked tin oxide/polymer composite gel electrolyte with adjustable porosity for enhanced sodium ion batteries
A cross-linked tin oxide/polymer composite gel electrolyte with adjustable porosity for enhanced sodium ion batteries
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DOI：
10.1016/j.cej.2021.133922
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发表时间：
2021-12
影响因子：
15.1
通讯作者：
Yue Zhao;Hongbin Liu;Xianhe Meng;Anmin Liu;Yun Chen;T. Ma
中科院分区：
文献类型：
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作者：
Yue Zhao;Hongbin Liu;Xianhe Meng;Anmin Liu;Yun Chen;T. Ma
固体电解质在锂/钠离子电池中具有取代传统易燃液体电解液的巨大潜力。然而，固体电解质的离子电导率低，界面性能差，很难达到常规液体电解质体系的水平。现在我们通过接触PVDF-HFP和SnO2构建了一个可调节的多孔三维网络结构，并通过添加1-(4-氰基苯基)胍优化了凝胶聚合物电解质中的离子传导路径。具有三维网络结构的PVDF-HFP为钠离子的储存和运输提供了通道，1-(4-氰基苯基)胍的亚氨基氮原子可以与钠离子形成配体，从而增强Na+的传导。得到的凝胶聚合物电解质在70℃时的离子电导率为0.232 ms cm−1，且易于与阳极形成稳定的界面层。进一步的实验表明，与液体电解液相比，PSGGSE与阳极之间形成了更稳定的界面。对Na/PSGGSE/Na对称电池在不同电流密度下的循环试验表明，电池在400h后没有短路现象，说明电池不会短路，PSGGSE能有效地抑制Na枝晶的生长。此外，Na/PSGGSe/NiMoO4电池在100mA g−1的电流密度下具有优异的循环稳定性，200次循环后仍保持150mA g−1的高容量，远高于液体电解液。
Solid electrolytes have a great potential to replace traditional flammable liquid electrolytes for lithium/sodium ion batteries. However, the solid electrolytes have a low ionic conductivity and poor interface properties, so it is difficult for them to reach the level of conventional liquid electrolyte systems. We have now built an adjustable porous 3D network structure by contacting PVDF-HFP and SnO2, and optimized the ion conductive path in the gel polymer electrolyte by adding 1-(4-cyanophenyl)-guanidine. PVDF-HFP with a 3D network structure provides a channel for storing and transporting sodium ions, and the imino nitrogen atom of 1-(4-cyanophenyl)guanidine can form a ligand with sodium ions to enhance the conduction of Na+. The gel polymer electrolyte (PSGGSE) thus obtained has an ion conductivity of 0.232 mS cm−1at 70 °C, and is easy to form a stable interface layer with the anode. Further experiments showed that compared with liquid electrolytes, a more stable interface was formed between PSGGSE and the anode. Cycling tests of Na/PSGGSE/Na symmetric batteries under different current densities showed that no short circuit occurred after 400 h, indicating that the battery could not be short-circuited, and PSGGSE can effectively inhibit the growth of Na dendrites. In addition, the Na/PSGGSE/NiMoO4battery has an excellent cycling stability at the current density of 100 mA g−1, and still maintains a high capacity of 150 mAh g−1after 200 cycles, which is much higher than that of liquid electrolytes.