Ionic–Electronic Coupling Enables Stable and Precise Memristive Switching through Reversible Crystalline–Solid Solution Transition

Coupled ionic–electronic effects offer intriguing opportunities for the development of next-generation memristive devices. Layered two-dimensional transition metal chalcogenides, in particular, enable controllable ion migration and efficient ionic coupling among devices, providing a promising platform for ion-regulated functionalities. However, repeated ion intercalation/deintercalation can cause structural degradation, limiting device stability. Here, we report a lithium-ion-regulated memristor based on hexagonal-phase VS₂ nanoflakes, exhibiting reversible and highly linear conductance tuning. The device shows symmetric responses under periodic voltage pulses and achieves 32 stable conductance states with excellent retention and endurance. In situ transmission electron microscopy and Raman spectroscopy reveal that conductance modulation arises from a reversible crystalline–solid solution transition induced by lithium-ion intercalation/deintercalation, effectively suppressing structural degradation. Our work establishes a direct link between ion dynamics, lattice evolution, and electronic transport, demonstrating the potential of crystalline–solid solution processes for designing stable, high-precision ionic devices.