Synthesis of Bis(dodecylammonium) Tetrachlorocuprate Using Ball Milling for Thermal Energy Storage

Layered hybrid halometallates are highlighted for their adaptable thermal, electrical, and optical properties by modifying the alkylammonium or metal constituents. However, the conventional synthesis procedures of these materials present some sustainability and scalability issues. To tackle these issues, mechanochemistry is a promising alternative synthesis which uses mechanical energy and can reduce the solvent content required. Mechanochemical synthesis has proven to be an effective synthesis route for various perovskite structures, but research on bis-(alkylammonium) tetrahalometallates is limited. Here, we explore the feasibility of synthesizing bis-(alkylammonium) tetrahalometallates through ball milling and reducing solvent usage. Crystal and molecular results confirmed the successful synthesis with minimal impurities, <5 wt %. The bis-(alkylammonium) tetrahalometallates obtained through ball milling presented comparable enthalpy and specific heat values to those obtained through traditional synthesis routes. Moreover, the ball milling synthesis consumed significantly less energy and solvent and led to higher reaction yield than the traditional synthesis methods, thereby enhancing the sustainability of the process. Overall, the results validate the synthesis through ball milling as a viable and environmentally efficient method for bis-(alkylammonium) tetrahalometallates.