Interlayer-Expanded MoS₂/N-Doped Carbon with Three-Dimensional Hierarchical Architecture as a Cathode Material for High-Performance Aluminum-Ion Batteries

Aluminum-ion batteries (AIBs) have drawn remarkable attention because of the large capacity, inexpensiveness, and abundance of Al in nature. However, the low capacity and poor cycle life of the cathode materials tremendously hinder their development. The fabrication of interlayer-expanded MoS₂/N-doped carbon (MNC) with a three-dimensional (3D) hierarchical tremella structure through a hydrothermal treatment and calcination is described in this work. As cathode materials, MNC shows decent capacity and superior cycle stability. Remarkably, the MNC electrode presents a capacity as high as 191.2 mAh g^-1, following 450 cycles with a current density of 0.5 A g^-1. Moreover, the MNC electrode presents a specific capacity of 127.5 mAh g^-1, following 1700 cycles at 1A g^-1, and the associated Coulomb efficiency reaches 99.5%. The unique 3D hierarchical structure and interlayer spacing, which reach up to 0.82 nm, reduce the diffusion path for Al³⁺, boost the diffusion of Al³⁺, and provide more active sites. Meanwhile, N-doped carbon is beneficial to promote electronic conductivity and maintaining structural integrity during cycles. The insertion and extraction mechanism of Al³⁺in MNC has been put forward and confirmed to understand its outstanding electrochemical performance. This study exhibits a strategy to obtain advanced AIB electrode materials through 3D hierarchical architecture design.