Self‐Heating and Thermal Gradient in Solid‐State Batteries: Friend or Foe?

ABSTRACT Solid‐state batteries (SSBs) are poised to tackle the growing demands of electrified mobility due to their superior energy and power density with enhanced safety. Realizing their potential necessitates overcoming fundamental mechanistic challenges, including solid–solid point contacts, chemo–mechanical interactions, and interfacial instability. Here, we uncover the underpinning origins of dynamic thermo‐electrochemical gradients and intrinsic heat generation during operation. By harnessing their self‐heating signature under thermally modulated environments, we delineate design spaces that integrate materials, electrode configurations, and operational regimes, enabling performance improvements through enhanced thermal responsiveness. The directionality of thermal gradients is critically informed by the cathode architecture and correlates to the resulting temperature profiles, gradients, and interface stability. Further, we present a compelling case for transitioning to anode‐free SSBs that yield greater thermal utilization and performance benefits from self‐heating. Our novel Generate‐Retain‐Intensify‐Direct (GRID) workflow based on a mechanism‐centric SSB design, highlights its intrinsic thermal signature as a key lever for high‐power applications.