Controllable and Reversible Soft Shorts within Solid-State Lithium-Ion Conductors for Potential Memristor Applications

Soft shorts are normally considered as the “invisible killers” of lithium-ion batteries because they are unpredictable, uncontrollable, and irreversible. In this work, a flexible and effective strategy based on femtosecond laser etching is proposed to construct usable soft shorts within solid-state lithium-ion conductors via microstructure design and electric field modulation. In the Li6.5La3Zr1.5Ta0.5O12 model system, the composition of the ionic and electronic transport can be effectively modulated by the assembly pressure. The underlying mechanism governing the microstructure-induced soft shorts involves pressure-driven microcracks propagating along grain boundaries, enabling lithium metal to creep and form conductive filaments. Inspired by biological synapses, a model memristor is designed based on the microstructure-induced soft shorts and demonstrated with excellent controllability and stability. These findings open potential opportunities for the development of next-generation neuromorphic devices.