Tailored Terminal Groups in MXenes for Fast-Charging and Safe Energy Storage

The development of metal-ion batteries (MIBs) necessitates advanced thermal management strategies to prevent thermal runaway and ensure safe operation during rapid charging and discharging, particularly under elevated temperatures. While traditional thermal management approaches focus predominantly on optimizing separators and electrolytes, innovative electrode materials can significantly enhance these efforts. This chapter explores the potential of surface-terminated MXenes with exceptional electrical conductivity and low infrared emissivity to improve thermal regulation in MIBs. Recent advances in one-step organic Lewis acid-assisted gas-phase reaction complemented by vacuum filtration to prepare a variety of tailored MXenes have been developed to integrate high-rate capacity with reduced heat generation during ion storage. Typically, Se-terminated Nb2CSe2 demonstrates a remarkable 1.5-fold enhancement in Li+-storage capacity, achieving ~220 mAh·g−1 at a current density of 1 A·g−1 by the fifth cycle. This performance improvement stems from superior electrical conductivity, structural stability, and high mid-infrared permittivity, which contribute to minimized thermal radiation. Additionally, computational analyses highlight that the alignment of enhanced permittivity and conductivity along the z-direction significantly reduces heat radiation from these electrodes. This chapter underscores the potential of tailored terminal groups in various MXenes, emphasizing how engineered surface functionalities can lead to the development of flexible electrodes with intrinsic self-thermal management capabilities for the safe and efficient energy storage of fast-charging MIBs. The insights provided herein illuminate the role of surface-terminated 2D materials in advancing the performance and safety of next-generation energy storage technologies.