Petroleum coke-derived porous carbon encapsulating phase change materials for solar-thermal-electricity output

Solar energy utilization is hindered by intermittency, highlighting the urgency of advanced thermal energy storage technologies. Phase change materials (PCMs) are promising candidates but suffer from leakage and poor photothermal performance. Herein, we fabricate hierarchically porous carbon (PCPC) from petroleum coke (a refinery by-product) via a salt-templating method, which serves as an efficient support for paraffin wax (PW) PCMs. Benefiting from the unique porous structure of PCPC, the resulting form-stable composite PCM (PW/PCPC) exhibits remarkable performance, including a high latent heat of 134.4 J g−1, excellent structural stability, and outstanding cycling durability. Simultaneously, the composite realizes an outstanding photothermal conversion efficiency of 89.68%. A key breakthrough is the development of an integrated solar-thermal-electricity conversion system by combining PW/PCPC with a commercial thermoelectric generator. This system delivers a stable power output density of 7.01 W m−2 and can continuously generate electricity using stored thermal energy even after light source removal. This work not only provides a waste valorization strategy for high-performance composite PCMs but also demonstrates their great potential in efficient solar energy harvesting and sustainable power supply, addressing critical challenges in solar energy utilization.