Wet combustion synthesis of new thermochemical energy-storage materials based on carbide slag/magnesium oxide using citric acid

In this study, industrial solid waste carbide slag (as the calcium source) is modified using the critic acid (as the fuel) combustion mixing method to prepare a new type of magnesium oxide–doped energy-storage material. The experimental results show that the prepared H2O-CM-100 material doped with magnesium oxide exhibits good energy-storage performance and cycling stability during calcium cycling. After 20 energy-storage cycles, the energy-storage density and effective conversion rate remained stable at 1800 kJ/kg and 0.57, respectively. These values exceed the reported energy-storage densities and effective conversion rates of carbide slag energy-storage materials modified using the dry physical mixing method employed in previous studies. In addition, the carbonation kinetics results indicate that the doping of magnesium oxide effectively improves the carbonation reaction rate of carbide slag materials in the carbide slag cycle. In summary, magnesium oxide doping can not only improve the sintering of calcium oxide particles in carbide slag materials but also effectively enhance the energy-storage performance and carbonation reaction rate of carbide slag during carbide slag cycles. Thus, this study proposes a novel method for the efficient resource utilization of carbide slag and development of energy-storage materials.