Beijing Advanced Innovation Center for Materials Genome Engineering, Institute of Advanced Materials and Technology, University of Science and Technology Beijing , Beijing 100083, China.
ACS Appl Mater Interfaces. 2018 Feb 28;10(8):7069-7078. doi: 10.1021/acsami.7b18123. Epub 2018 Feb 20.
Replacement of flammable organic liquid electrolytes with solid Li conductors is a promising approach to realize excellent performance of Li metal batteries. However, ceramic electrolytes are either easily reduced by Li metal or penetrated by Li dendrites through their grain boundaries, and polymer electrolytes are also faced with instability on the electrode/electrolyte interface and weak mechanical property. Here, we report a three-dimensional fiber-network-reinforced bicontinuous solid composite electrolyte with flexible Li-conductive network (lithium aluminum titanium phosphate (LATP)/polyacrylonitrile), which helps to enhance electrochemical stability on the electrode/electrolyte interface by isolating Li and LATP and suppress Li dendrites growth by mechanical reinforcement of fiber network for the composite solid electrolyte. The composite electrolyte shows an excellent electrochemical stability after 15 days of contact with Li metal and has an enlarged tensile strength (10.72 MPa) compared to the pure poly(ethylene oxide)-bistrifluoromethanesulfonimide lithium salt electrolyte, leading to a long-term stability and safety of the Li symmetric battery with a current density of 0.3 mA cm for 400 h. In addition, the composite electrolyte also shows good electrochemical and thermal stability. These results provide such fiber-reinforced membranes that present stable electrode/electrolyte interface and suppress lithium dendrite growth for high-safety all-solid-state Li metal batteries.
用固体 Li 导体替代易燃有机液体电解质是实现优异 Li 金属电池性能的一种很有前途的方法。然而，陶瓷电解质要么容易被 Li 金属还原，要么通过晶粒间界被 Li 枝晶穿透，聚合物电解质也面临着电极/电解质界面不稳定和机械性能弱的问题。在这里，我们报告了一种具有柔性 Li 导电网络（磷酸钛铝锂 (LATP)/聚丙烯腈）的三维纤维网络增强双连续固体复合电解质，它有助于通过隔离 Li 和 LATP 来增强电极/电解质界面的电化学稳定性，并通过纤维网络的机械增强来抑制 Li 枝晶生长，从而提高复合固体电解质的性能。该复合电解质与 Li 金属接触 15 天后表现出优异的电化学稳定性，与纯聚（氧化乙烯）-双三氟甲烷磺酰亚胺锂盐电解质相比，拉伸强度（10.72 MPa）增大，因此具有长期稳定性和安全性，Li 对称电池在 0.3 mA cm 的电流密度下稳定运行 400 h。此外，该复合电解质还表现出良好的电化学和热稳定性。这些结果为高安全性全固态 Li 金属电池提供了具有稳定电极/电解质界面和抑制 Li 枝晶生长的纤维增强膜。
