Smart Solid‐State Interphases Enable High‐Safety and High‐Energy Practical Lithium Batteries

Abstract With the electrochemical performance of batteries approaching the bottleneck gradually, it is increasingly urgent to solve the safety issue. Herein, all‐in‐one strategy is ingeniously developed to design smart, safe, and simple (3S) practical pouch‐type LiNi 0.8 Co 0.1 Mn 0.1 O 2 ||Graphite@SiO (NCM811||Gr@SiO) cell, taking full advantage of liquid and solid‐state electrolytes. Even under the harsh thermal abuse and high voltage condition (100 °C, 3–4.5 V), the pouch‐type 3S NCM811||Gr@SiO cell can present superior capacity retention of 84.6% after 250 cycles (based pouch cell: 47.8% after 250 cycles). More surprisingly, the designed 3S NCM811||Gr@SiO cell can efficiently improve self‐generated heat T 1 by 45 °C, increase TR triggering temperature T 2 by 40 °C, and decrease the TR highest T 3 by 118 °C. These superior electrochemical and safety performances of practical 3S pouch‐type cells are attributed to the robust and stable anion‐induced electrode‐electrolyte interphases and local solid‐state electrolyte protection layer. All the fundamental findings break the conventional battery design guidelines and open up a new direction to develop practical high‐performance batteries.