Highly efficient low-temperature thermal storage of phase change brine gels with synchronously enhanced thermophysical property and mechanical property towards biopharmaceutical cold chain

The application of phase change brine gels (PCBGs) in low-temperature thermal storage has shown significant promise. However, their application is still hindered by limitations in both thermophysical property and mechanical property. This study proposes an effective solution to synchronously enhance thermophysical property and mechanical property of PCBGs. The sulfate ions in brine trigger the Hofmeister effect in carrageenan-hydroxyapatite (HAP) double network to significantly increase the mechanical strength from 80.31 kPa to 227.12 kPa, with a remarkable stretchability enhancement to 151.28 %. By providing abundant hydrogen bonding sites, the carrageenan-HAP double network efficiently loads the brine. PCBGs present outstanding cycle stability, no leakage, a phase change temperature of −16.74 °C and a melting latent heat of 145.04 J g −1 . Moreover, the addition of graphite flakes enhances the thermal conductivity of PCBGs to 1.323 W m −1 K −1 , representing a 272.22 % improvement. Notably, HAP further imparts exceptional flame-retardant properties to PCBGs. Finally, PCBGs are used to manufacture cold storage equipment presenting superior low-temperature environment, effectively ensuring the activity of glucose oxidase. This work provides forward-looking guidance for efficient low-temperature thermal storage in cold chain logistics. • Low-temperature thermal storage performance and mechanical property of PCBGs is synergistically enhanced. • PCBGs show high melting enthalpy, no leakage and superior cycle stability. • PCBGs demonstrate a mechanical strength of 227.12 kPa and a stretchability enhancement of 151.28 % • PCBGs demonstrate efficient cold energy utilization in biomedical cold chain.