Directed and Continuous Interfacial Channels for Optimized Ion Transport in Solid-State Electrolytes

The traditional strategy of using polymer solid electrolyte composite fillers is extremely limited by the continuity of the organic-inorganic interface. Herein, a new composite electrolyte is fabricated, wherein alternating layers of organic polyethylene oxide (PEO) and inorganic molybdenum trioxide (MoO 3 ) nanobelts are prepared and then the multilayer film is rolled and sliced into disks. Compared with a similar electrolyte prepared by disordered blending, the electrolyte here has a mesoscopic continuous organic-inorganic interface perpendicular to the electrode direction. The ionic conductivity increases from 4.88 × 10 −4 to 1.16 × 10 −3 S cm −1 . The “interfacial battery” can operate stably over >2000 charge–discharge cycles at 2 C (60 °C), and can withstand rapid charging–discharging, even at 10 C. Theoretical calculation results show that this unique assembly method essentially eliminates the energy band gap between the PEO and MoO 3 interface, and promotes lithium ion (Li + ) transport. In addition, the electronic interaction between the orbital of Mo and PEO extends the lattice structure of PEO, resulting in a reduction in the crystallinity, which further improves the battery performance. This study provides a composite electrolyte design that is different from blending and represents a new strategy for the development of low-cost superionic conductors.