Unveiling Confinement Engineering for Achieving High‐Performance Rechargeable Batteries

The confinement effect, restricting materials within nano/sub-nano spaces, has emerged as an innovative approach for fundamental research in diverse application fields, including chemical engineering, membrane separation, and catalysis. This confinement principle recently presents fresh perspectives on addressing critical challenges in rechargeable batteries. Within spatial confinement, novel microstructures and physiochemical properties have been raised to promote the battery performance. Nevertheless, few clear definitions and specific reviews are available to offer a comprehensive understanding and guide for utilizing the confinement effect in batteries. This review aims to fill this gap by primarily summarizing the categorization of confinement effects across various scales and dimensions within battery systems. Subsequently, the strategic design of confinement environments is proposed to address existing challenges in rechargeable batteries. These solutions involve the manipulation of the physicochemical properties of electrolytes, the regulation of electrochemical activity, and stability of electrodes, and insights into ion transfer mechanisms. Furthermore, specific perspectives are provided to deepen the foundational understanding of the confinement effect for achieving high-performance rechargeable batteries. Overall, this review emphasizes the transformative potential of confinement effects in tailoring the microstructure and physiochemical properties of electrode materials, highlighting their crucial role in designing novel energy storage devices.