Engineering the Surface/Interface of Horizontally Oriented Carbon Nanotube Macrofilm for Foldable Lithium‐Ion Battery Withstanding Variable Weather

Abstract Flexible lithium‐ion batteries attract extensive attention in wearable electronics but are limited by severe capacity loss under extreme weather due to the poor flexible current collector. Herein, a horizontally oriented carbon nanotube macrofilm (HUCNM) with excellent electrical conductivity and tuned electrolyte wettability through engineering the surface/interface of HUCNM is reported for foldable batteries, which exhibits a high capacity of 700 mAh with excellent flexibility and stable charge/discharge rate performance in several extreme conditions. Such amazing results are ascribed to the excellent contact and interaction among the current collector, active material, and electrolyte, which is rising from the surface/interface engineering of carbon nanotube films. This work provides useful insights in the engineering of the surface/interface of carbon current collectors, and revolutionizes the traditional design for wearable electronics, transcending these devices beyond their current limitations.