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

Abstract 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 (MoO₃) 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 MoO₃ 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.