Cation-Driven Valence Change Mechanism in 2D AgCrS2 for Ultralow-Power and Reliable Memristors.

Memristive devices are promising building blocks for next-generation memory and neuromorphic circuits in artificial intelligence. Among them, filamentary memristors offer great potential for high-performance and densely integrated systems. However, achieving both low-power operation and long-term cycling stability remains a key challenge. Here, we present a 2D AgCrS2 volatile memristor that operates via a novel cation-driven valence change mechanism (CVCM). Unlike traditional filament-based conduction, this mechanism enables Ag+-driven switching without metal filament growth. The threshold switching process is governed by the reversible intercalation of highly mobile Ag+ ions into tetrahedral vacancies between CrS2 layers, forming and rupturing the highly conductive Ag2CrS2 pathway and thus delivering an on/off ratio exceeding 105 at 0.1 V. The AgCrS2 memristor enables a reduced threshold voltage of 0.2 V and an ultralow power consumption down to 200 pW when the compliance current is further reduced to the nA level. Additionally, the absence of elemental Ag metallization in the switching layer prevents structural degradation, enabling stable operation for over 3 × 105 switching cycles. These findings establish CVCM as a promising way for developing energy-efficient and reliable memristive technologies.