MXenes for solid-state batteries: Progress, challenges, and perspectives for advanced energy storage

Solid-state batteries (SSBs) are emerging as a transformative solution for high-energy-density and intrinsically safe energy storage systems. Challenges, such as low ionic conductivity, poor interfacial contact, and lithium dendrite formation, continue to impede their large-scale adoption despite significant advances in electrochemical stability, thermal resilience, and compact cell design. MXenes are a novel family of 2D transition metal carbides and nitrides that have shown great promise to overcome these limitations due to their tunable surface terminations, high conductivity, and structural versatility. This review explores the recent breakthroughs in MXene-integrated all SSBs. It delves into their roles as functional fillers in solid-state electrolytes (SSEs) as well as interfacial layers, electrodes, and current collectors. We discuss synthesis strategies, surface engineering, and design principles that enable MXenes to enhance ionic transport, suppress dendrite growth, and improve interfacial compatibility. A foundational overview of MXene physicochemical properties that are relevant to SSBs is provided in addition to an evaluation of the key SSE characteristics. Finally, the review outlines critical challenges and future directions for the rational design of MXene-enabled SSB architectures. This review aims to accelerate the development of safe, durable, and high-performance SSBs by bridging a fundamental understanding with application-driven innovation.