Suppressing agglomeration in salt hydrate reactors via lattice architecture

Salt hydrates are a promising class of thermochemical energy storage materials (TCMs) for heat storage applications. However, their practical deployment is hindered by severe particle agglomeration, especially at large scale, which limits cyclability and leads to performance degradation in conventional packed-bed reactors. Here, we propose and experimentally validate a novel lattice-structured reactor bed designed to overcome these limitations. The engineered lattice geometry promotes uniform mass transport and mitigates bulk agglomeration, resulting in significantly improved long-term stability and energy performance. Compared to a traditional packed bed, the lattice-structured configuration maintains over 98% of its initial thermal output after 10 (de)hydration cycles, whereas the packed bed retains less than 50% under the same operating conditions. The lattice system delivers a 76.8% higher thermal energy output than the packed bed. Remarkably, after 15 cycles, the lattice bed exhibited an 8% increase in heat release relative to the initial cycle, indicating self-optimizing behavior over time. The micro-CT results suggest that the lattice architecture constrains agglomeration to the scale of individual unit cells, thereby potentially limiting the formation of larger, bed-scale agglomerates. However, minor cracking was observed between unit cells at the base of the reactor. Subsequent computational fluid dynamics (CFD) analysis revealed that these cracks, along with increased porosity around lattice walls, redistribute vapor flow, activate previously stagnant regions, and promote more homogeneous water uptake throughout the bed. These findings demonstrate the potential of lattice-structured reactor designs to enable durable, efficient, and scalable thermochemical energy storage solutions, supporting the broader integration of renewable energy systems.