Electrochemomechanical Modeling and In Situ Measurement of Transition Metal Dichalcogenides-Based Electrochemical Actuators

Abstract

Since working voltages are much higher than water electrolysis voltage, traditional ionic electroactive polymers (IEAPs) such as ionomeric polymer-metal composites and conjugated polymers still face the great challenges like back relaxation, leakage and evaporation of electrolyte. Newly developed transition metal dichalcogenides (TMDs)-based IEAP, which can be driven by the voltage as low as 0.3 V, becomes a promising candidate to overcome those challenges. Herein, an electrochemomechanical model, coupling ions intercalation and chemical reaction, is proposed for the first time to explain the mechanism of TMDs-based IEAPs. To further validate the model, molybdenum disulfide/Aluminum electrochemical actuators (EAs) are fabricated. Then chemical and mechanical performance of the EAs are recorded in situ during actuation. A good agreement is achieved by comparing theoretical and experimental results. A model study is performed to predict the effects of scan rate, working temperature and PH value of the electrolyte on curvature evolution. Results show that scan rate and temperature can hardly influence curvature amplitude while PH value of the electrolyte greatly affects curvature evolution. Moreover, response rate of EAs increases with scan rate. An optimal thickness ratio of 0.5 is also found for bilayered EAs. This study paves a new way for promoting the development of TMDs-based IEAPs.