Thermoplastic Network Formation as a Method for Stabilizing Salt Hydrate Particles

Thermochemical energy storage (TCES) utilizes chemical reactions to store thermal energy, offering a promising solution for efficient energy management. However, a significant challenge in application of TCES materials, particularly with crystal-to-crystal chemical transformations, is the mechanical degradation of reactive particles during repeated cycles connected with the constant re-modeling of crystals due to consecutive hydration-dehydration steps. This degradation leads to increased pressure drops in packed beds due to swelling and fracturing of salt particles, complicating their practical application. To address this issue, this study investigates the effect of a polymeric network as stabilizing element within TCES particles to enhance mechanical stability. Using potassium carbonate hydrate (K₂CO₃·1.5H₂O) as a model thermochemical material and thermoplastic polymers for reinforcement, composite particles were developed to resist disintegration over multiple cycles. The incorporation of polymeric networks from polyamide (PA11), polyetherimide (PEI) and polyvinylidene fluoride (PVDF) resulted in improved mechanical properties at relatively high porosity, which contributes to higher hydration rate. The developed stabilization method is compatible with existing scalable particle production methods like tableting and compacting.