Work

Adaptive Voiding Enables Interfacial Morphological Control at Low Stack Pressure in Solid-State Batteries

Year: 2026

Type: preprint

Abstract: Solid-state batteries with alkali metal anodes offer high energy density and improved safety, but their performance is hindered by void formation at the metal-solid electrolyte interface during metal stripping, leading to impedance rise and increased probability of dendrite formation upon plating. Here, we demonstrate that low concentrations (<5 vol%) of potassium metal added to industrial-grade lithium metal creates a dispersed Na-K liquid phase that suppresses voiding and enables stable, high-capacity stripping at practical current densities and stack pressures below 1 MPa. We furthermore identify a low-frequency oscillatory impedance attributed to “adaptive voiding”—the cyclic expansion and contraction of interfacial voids arising from an interplay between void growth and lithium deformation. This behavior, revealed by cryo-PFIB imaging and electrochemical analysis, offers a diagnostic signature for evaluating interfacial stability. These findings highlight new opportunities for designing robust, high-capacity SSBs operable under realistic mechanical constraints by controlling dynamic interfacial morphologies.

Source: ChemRxiv

DOI: 10.26434/chemrxiv.15000881/v2