Robust cement-graphite thick electrode enables high-performance molten salt aluminum batteries

Molten-salt aluminum batteries are promising for grid-scale energy storage, leveraging the abundance and recyclability of aluminum along with the intrinsic safety, non-flammability, and high ionic conductivity of chloroaluminate electrolytes. However, conventional polymeric binders lack stability in high-temperature, corrosive molten-salt environments, leading to electrode structural degradation and premature battery failure. Here we propose thick cement-graphite electrodes for molten salt aluminum batteries that feature a self-supporting structure, high mechanical strength, high thermal tolerance, and resistance to chemical corrosion. In this design, graphite provides continuous electron-conducting pathways, while hydrated cement phases encapsulate and interconnect graphite, forming an inorganic skeleton with measurable mechanical properties, chemically inert, and hierarchically porous. Operating at 150 °C, the Al| |cement-graphite cells achieve a long cycle life of over 11,000 cycles at 16 mg cm–2 and 10 A g–1, rate capability (retaining nearly 80 mAh g–1 at 15 A g–1) and stable cycling performance under high mass loadings up to 100 mg cm–2. After extended cycling, the cement-graphite electrode retains its structural integrity. Multi-cell assemblies demonstrate scalability, while cost analysis shows cost savings associated with cement binders for molten-salt batteries. Molten salt aluminum batteries face electrode degradation from traditional polymer binders in high-temperature, corrosive environments. Here, authors develop robust self-supporting cement-graphite thick electrodes as a low-cost inorganic alternative. The electrodes deliver over 11,000 stable cycles, good rate performance and reliable operation at high material loadings, with scalable production and lower overall battery costs.