In thermal-energy-storage systems that use ice slurry as the working fluid, the shape and size of the crystals must be optimized during the ice creation process. Therefore, methods for preventing ice from recrystallizing during long-term storage and long-distance transport should be developed. Here, for use in ice-slurry systems, we studied two potential additives in solution (concentration of 5mg/ml), Tween surfactants and Polyvinyl Alcohol (PVA), and compared their capability to inhibit recrystallization and to inhibit ice crystal growth with that of pure water and antifreeze proteins (AFPs). For Tween, we studied Tween 80, 81, and 85, and for PVA, we studied three different molecular weights (31000-50000, 89000-98000, and 124000-186000 separately). The inhibition of ice crystal growth was determined by optical microscopy, and the inhibition of recrystallization by the splat cooling method. The results showed that, among the additives studied here, PVA of molecular weight 31000-50000 was relatively more effective in inhibiting recrystallization and had better long-term solubility properties, thus making it a potential additive in ice-slurry cold-storage systems.