High Selenium Loading in Vertically Aligned Porous Carbon Framework with Visualized Fast Kinetics for Enhanced Lithium/Sodium Storage

Abstract

AbstractLithium/sodium–selenium (Li/Na–Se) batteries with high volumetric specific capacity are considered promising as next‐generation battery technologies. However, their practical application is hindered by challenges such as low Se loading in cathodes and the polyselenides shuttle effect. To address these challenges, a new Se host is introduced in the form of a free‐standing N, O co‐doped vertically aligned porous carbon framework decorated with a carbon nanotube forest (VCF‐CNTs), allowing for high mass loading of up to 16 mg cm−2. The low‐tortuosity Se@VCF‐CNTs architecture facilitates rapid lithiation/sodiation kinetics, while the CNT forests in vertical microchannels enhance efficient Se loading and serve as a multi‐layer fence to prevent undesired polyselenide shuttling. Consequently, the Se@VCF‐CNTs cathode displays a significant areal capacity of 10.3 mAh cm−2 at 0.1 C with a Se loading of 16 mg cm−2 for Li–Se batteries, exceeding that of commercial lithium ion batteries (4.0 mAh cm−2). In Na–Se batteries, the Se@VCF‐CNTs electrode with a Se loading of 5 mg cm−2 exhibits a discharge capacity of 436 mAh g−1 after 200 cycles, proving its consistent cycling performance. This study enriches the field of knowledge concerning high‐loading Se‐based battery systems, offering a promising avenue for enhancing energy density in the field.