Micro-stress pump with stress variation to boost ion transport for high-performance sodium-ion batteries

Abstract

Sluggish kinetics limit the practical application of sodium-ion batteries (SIBs); thus, innovative strategies and the design of materials with fast reaction kinetics are important for the development of SIBs. To solve these issues, the innovative strategy of using a micro-stress pump to boost Na⁺ transport by simulating rhythmic cardiac blood pumping has proposed for the first time. A smart material with cardiac-like behavior promotes the electrochemical kinetics through the self-regulation of stress under the variation of voltage in the redox reaction. Under the micro-stress field, a half-cell demonstrates a capacity of 119.1 mA h g⁻¹ at 35 A g⁻¹, and a 1.04 A h pouch cell shows an excellent energy density of 317.2 W h kg⁻¹ (the retention is 90.2% after 500 cycles at 1C). Via further analysis of physicochemical characterizations and the sensor signal, the signal correlation of the mechanism between electrochemistry and stress was obtained. This work provides a strategy for accelerating the transmission rate of Na⁺ based on a stress field.