Rapid and stable calcium-looping solar thermochemical energy storage via co-doping binary sulfate and Al–Mn–Fe oxides

Solar thermochemical energy storage based on calcium looping(CaL)process is a promising technology for next-generation concentrated solar power(CSP)systems.However,conventional calcium carbonate(CaCO_(3))pellets suffer from slow reaction kinetics,poor stability,and low solar absorptance.Here,we successfully realized high power density and highly stable solar thermochemical energy storage/release by synergistically accelerating energy storage/release via binary sulfate and promoting cycle stability,mechanical strength,and solar absorptance via Al–Mn–Fe oxides.The energy storage density of proposed CaCO_(3)pellets is still as high as 1455 kJ kg^(-1)with only a slight decay rate of 4.91%over 100 cycles,which is higher than that of state-of-the-art pellets in the literature,in stark contrast to 69.9%of pure CaCO_(3)pellets over 35 cycles.Compared with pure CaCO_(3),the energy storage power density or decomposition rate is improved by 120%due to lower activation energy and promotion of Ca^(2+)diffusion by binary sulfate.The energy release or carbonation rate rises by 10%because of high O^(2-)transport ability of molten binary sulfate.Benefiting from fast energy storage/release rate and high solar absorptance,thermochemical energy storage efficiency is enhanced by more than 50%under direct solar irradiation.This work paves the way for application of direct solar thermochemical energy storage techniques via achieving fast energy storage/release rate,high energy density,good cyclic stability,and high solar absorptance simultaneously.

Air to fuel:Direct capture of CO_(2)from air and in-situ solar-driven conversion into syngas via Ni_(x)/NaA nanomaterials

Ever-increasing CO_(2)emissions and atmospheric concentration mainly due to the burning of traditional fossil fuels have caused severe global warming and climate change problems.Inspired by nature’s carbon cycle,we propose a novel dual functional catalyst-sorbent to tackle energy and environmental problems simultaneously via direct capture of CO_(2)from air and in-situ solar-driven conversion into clean fuels.Economically and operationally advantageous,the planned coupling reaction can be carried out in a single reactor without the requirement for an extra trapping device.The great CO_(2)capture and conversion performance in an integrated step is shown by the CO_(2)capacity of up to 0.38 mmol·g^(−1)for adsorption from 500 ppm CO_(2)at 25℃and the CO_(2)conversion rate of up to 95%.Importantly,the catalyst-sorbent is constituted of a nonprecious metal Ni catalyst and an inexpensive commercially available CO_(2)sorbent,viz,zeolite NaA.Furthermore,this designed dual functional material also exhibits outstanding stability performance.This work offers a novel pathway of capturing CO_(2)in the air at room temperature and converting it by CH4 into fuel,contributing to the new era of carbon neutrality.