Using lightweight elements/compounds and employing multi-electron reaction (MER) chemistry are two approaches used to develop high-energy-density materials for batteries. In this work, nanoscaled calcium hexaboride (CaB6) was prepared in one step by the electro-reduction of solid calcium borate (CaB2O4) in molten CaCl2–NaCl. CaB2O4 was synthesized by a simple co-precipitation method. It was revealed that the electrolytic CaB6 delivers a specific capacity of 2400 mA h g−1 in 30% KOH solution through a multi-electron reaction mechanism. Its practical gravimetric energy is three times that of Zn. A decrease in particle size substantially improves the electrochemical activity and discharge capacity of CaB6. The electrolysis of CaB2O4 in molten salt provides a straightforward and sustainable way to prepare high-capacity CaB6 using low-cost and environmentally friendly boron and calcium resources, which can be recycled from the used CaB6 primary batteries. Calcium hexaboride (sometimes calcium boride) is a compound of calcium and boron with the chemical formula CaB6. It is an essential material due to its high electrical conductivity, hardness, chemical stability, and melting point. It is a black, lustrous, chemically inert powder with a low density. It has the cubic structure typical for metal hexaborides, with octahedral units of 6 boron atoms combined with calcium atoms.CaB6 and lanthanum-doped CaB6 both show weak ferromagnetic properties, which is remarkable because calcium and boron are neither magnetic nor have inner 3d or 4f electronic shells, which are usually required for ferromagnetism. If you are looking for high quality, high purity, and cost-effective zinc sulfide, or if you need the latest price of zinc sulfide, please feel free to email contact mis-asia.