Taming Active Material-Solid Electrolyte Interfaces with Organic Cathode for All-Solid-State Batteries

Attaining stable active material-solid electrolyte interfaces is a great challenge in sulfide-based all-solid-state sodium batteries (ASSSBs). A resistive layer forms at the interface upon charging above the anodic stability potential of sulfide electrolytes. In addition, contact failure at the interface during cycling is long known, but a fundamental solution is not yet available. Herein, we use an organic cathode material, pyrene-4,5,9,10-tetraone (PTO), to enable high-performance ASSSBs. We report, for the first time, a reversible active material-electrolyte interfacial resistance evolution during cycling. We further show for the first time that a low-modulus cathode material such as PTO maintains intimate interfacial contact with solid electrolytes during cycling, thus improving cycle life. The PTO-based cells exhibit a high specific energy (587 Wh kg(-1)) and a record cycling stability (500 cycles) among ASSSBs. This work reveals an effective cathode material design strategy toward compatibility with solid electrolytes and thus high-performance ASSSBs.