Effect of nano-gallium capsules on thermal energy storage characteristics of manganese organometallic SS-PCM

Highlights: • Synthesis of SS-PCM with Mn as base metal, for TES was carried out by LPR method. • Nano gallium capsule by in-situ polymerisation with UF shell are highly stable. • MSS-PCM with n-Ga additive (wt.% of 1 & 5) was used to study thermal performance. • Latent heat and thermal conductivity of MSS-PCM/n-Ga increased by 13.5% and 26.8%. • The effect of 1000 thermal cycles were compared through FTIR, DSC and TGA. -- Abstract: This paper proposes the effect of nano-gallium capsules of weight fraction 1% and 5% on energy storage in manganese organo-metallic SS-PCM. Synthesis of MSS-PCM and encapsulation of liquid metal gallium was carried out by liquid phase reaction and in-situ polymerization method. The phase transition temperature and latent heat of the synthesized MSS-PCM is 38.39 °C and 73.83 kJ/kg for heating, 31.09 °C and 81.29 kJ/kg for cooling, respectively. The effect on the properties by adding n-Ga to MSS-PCM was investigated using FESEM, SEM, EDS, FTIR, DSC, TGA and LFA techniques. It was found that the maximum increase in enthalpy and thermal conductivity for MSS-PCM/n-Ga of wt.% (95%:5%) were 13.5% and 26.8%. The pure MSS-PCM, n-Ga and composite mixture were highly stable for 1000 cycles. TGA showed negligible change in thermal behaviour (RT-200 °C) and FTIR results confirmed that MSS PCM/n-Ga has good chemical stability after thermal cycling. Further it was concluded that MSS-PCM/n-Ga at 5% wt ratio has enormous potential for energy storage due to its thermal/chemical stability and high energy storage performance.