Unified iontronic sensing for operando monitoring of physical-chemical events in lithium-ion batteries

ABSTRACT Operando measurement of expansion force has become an effective way of monitoring physical-chemical events in lithium-ion batteries, of which the conventional optical means is limited by material fragility, structural incompatibility and system complexity. The utilization of flexible sensors can potentially address these challenges; however, their functionality and stability are restricted within hours in corrosive environments. Here, an in-situ unified iontronic sensing mechanism, derived from the super-capacitive electrode/electrolyte interface, is developed for expansion-force measurement in highly corrosive electrolyte environments. Specifically, it leverages the structural and material similarities between batteries and iontronic sensors to create a unified assessing device, utilizing only existing materials to produce in-situ detection. Consequently, the intelligence-incorporated architecture exhibits exceptional stability for continuous measurements over one month, enabling 400 charging/discharging cycles in a battery lifespan. Therefore, the unified iontronic sensing device, which has long-term on-board monitoring of expansion forces, offers an accurate and effective solution for the aging evaluation and safety pre-warning of lithium-ion batteries.