Construction of solid solution sulfide embedded in MXene@N-doped carbon dual protection matrix for advanced aluminum ion batteries

Engineering intriguing cathode electrode with desirable kinetics behaviors is imperative for boosting aluminum storage systems. Here, a MXene and N-doped carbon dually protected Ni0.6Co0.4S solid solution (Ni0.6Co0.4[email protected]@NC) composite is reported as the cathode material for AIBs. The dissolution of Ni into CoS lattice leads to the electronic rearrangement, tuning its binding interaction with the Al3+ and modifying the Al3+ diffusion barrier. Consequently, the Ni0.6Co0.4S renders the high overall Al3+ adsorbability, and contributes to fast Al3+ diffusion kinetics. Additionally, the robust [email protected] protective shell not only provides faster electron transfer pathway, but also contributes to high chemical and structural stability, attributed to the inhibition of active species dissolution and favorable tolerance to volume change. This novel design enables the Ni0.6Co0.4[email protected]@NC composite a high initial discharge capacity of 481.2 mA h g−1 at 400 mA g−1. Even at 1000 mA g−1, the capacity still maintains at 125.2 mA h g−1 after 300 cycles. Meanwhile, the investigation of reaction mechanism reveals that the cell involves the intercalation of Al3+ into Ni0.6Co0.4S to generate AllNimConS and elemental Ni and Co. This work propels the process of enhancement of electrochemical performance for AIBs via smart designing and constructing cathode materials.