Synergistic optimization of electronic and lattice structures through Ti-intercalation and Se-vacancy engineering for high-performance aluminum storage

Abstract

Layered chalcogenides play significant roles in electrochemical energy storage. However, their application potential is restricted by sluggish charge transfer and storage kinetics. Herein, a dual-defect strategy involving Ti intercalation and Se vacancies (SVs) is proposed to modulate the electronic structure of MoSe₂ and enhance the electrochemical performance of aluminum batteries (ABs). The dense atomic orbitals of Ti and Mo in Ti–MoSe_2−x contribute numerous electron states near the Fermi level, effectively filling the wide bandgap. This fundamentally activates the intrinsic electronic properties, elevating the charge-transfer ability. Moreover, the synchronous optimization of planar and interlayer structures endows the Ti–MoSe_2−x with ample active sites and expanded layer spacing, enhancing ion migration and electrochemical capacity. The significant charge interaction between Ti–MoSe_2−x and active electrolyte ions promotes the affinity and storage ability of cathodes for charge carriers. Owing to these merits, the Ti–MoSe_2−x cathode exhibits enhanced reversible capacity (250 mA h g⁻¹ at 0.5 A g⁻¹) and superior cycling stability (132 mA h g⁻¹ over 2400 cycles at 5.0 A g⁻¹) with fast reaction kinetics. This research offers in-depth insights into the electrochemical energy storage for ABs by modulating the electronic and lattice structures of layered chalcogenides.