Application of Ibuprofen Sodium Dihydrate for Thermochemical Energy Storage

ABSTRACT Thermochemical energy storage (TCES) can address grid instability by storing and releasing heat through reversible chemical reactions. However, recovery of low‐grade waste heat by conventional inorganic salt hydrates (ISH) is limited by deliquescence, corrosiveness, and poor cycling stability. In this study, organic salt hydrates (OSH) are investigated as an alternative platform for efficient and durable low‐temperature TCES. Ibuprofen sodium dihydrate (ISD) is identified as a model organic salt hydrate, exhibiting a dehydration temperature range of 60°C–110°C and a dehydration enthalpy of up to 59.5 kJ/mol (225 J/g) of water, comparable to ISH and compatible with industrial and residential waste heat streams. Comprehensive thermal and structural characterization demonstrates exceptional chemical and structural integrity over 150 hydration‐dehydration cycles, with a cycling efficiency of ∼99.9%, and high durability without deliquescence or pulverization, even under high humidity conditions. In situ characterization reveals that the transformation from ISD to ibuprofen sodium anhydrous involves structural reorganization, coupling chemical dehydration and phase transition to deliver higher energy storage capacity. A dual‐energy storage mechanism, paired with the design flexibility of organic molecular backbones, presents a promising design framework for creating next‐generation OSH that surpasses ISH performance for TCES applications and drives their sustainable deployment.