Dry Electrode Processing for High‐Performance Molten Salt Batteries

Abstract

AbstractMolten salt batteries (MSBs) are renowned for their rapid reaction kinetics, high safety, and cost‐effectiveness. However, their electrode design faces challenges due to polymer binder incompatibility in molten salt electrolytes (MSEs). To address this, an expanded graphite (EG) electrode is proposed through a dry electrode processing method for MSE‐based aluminum‐ion batteries. This method facilitates the fabrication of large‐area electrodes featuring high active material loadings of up to ≈60 mg cm−2. Notably, the EG electrode exhibits remarkable rate performance, achieving a specific capacity of 84.4 mAh g−1 in the AlCl3‐NaCl‐KCl MSE at 125 °C with a current density of 5 A g−1. This outstanding performance can be attributed to its rapid multi‐step intercalation reaction kinetics and well‐developed pore structure. Leveraging the chemical stability and fibrillization binding mechanism of the polytetrafluoroethylene binder, the electrode demonstrates longevity over 10,000 cycles, despite experiencing a three‐fold volume expansion. Additionally, a 100‐mAh‐scale Al‐EG full‐cell cycled 100 times with an energy efficiency of 78.7% at 500 mA underscores its potential for large‐scale applications. Considering the broad applicability of this approach, it can also provide crucial references and insights for electrode design across various MSB systems.