Despite the many positive developments of rechargeable lithium-ion batteries (LIBs), heat accumulation remains a safety concern. Preventing their overheating is difficult because of the existing technologies’ poor thermal management. This involves minimising the significant heat generated during battery charge and discharge. To address this issue, the Marie Skłodowska-Curie Actions SMARTBATT project aims to develop a thermoreversible liquid-solid transition electrolyte combined with inherent flame retardancy for LIBs. The design and synthesis will involve incorporating flame retardant into the electrolytes and producing a liquid-solid transition in them.