Alumina, sodium, and common salt are required. The chemical reaction converts sodium and nickel chloride into sodium chloride (common salt), nickel, and electrical energy. 

The overall reaction during battery discharge is: 

NiCl₂ + 2Na = Ni + 2NaCl + electrical energy 

The overall reaction during battery charging is: 

Electrical energy + 2NaCl + Ni = NiCl₂ + 2Na 

The reactants are sodium chloride (common salt); sintered nickel—impregnated with a molten salt solution of nickel chloride and sodium chloride—acting as the positive electrode; and liquid sodium acting as the negative electrode, separated from the other components by a separator. This separation is maintained by a ceramic wall permeable only to sodium ions; this wall separates the sodium electrode from the sodium chloride/nickel chloride/nickel electrode while simultaneously serving as the electrolyte. A key component of the ceramic is sodium-aluminum oxide (NaAl₁₁O₁₇); at temperatures of 270°C and above, sodium ions become sufficiently mobile to ensure adequate conductivity. An advantage is that the pure sodium metal at the negative electrode remains in a liquid state, preventing the formation of inactive or destructive compounds. 

In principle, this technology was developed back in the 1980s, originally for electric mobility. The system became known as the ZEBRA battery (Zero Emission Battery Research Activities). However, its energy density is not as high as that of lithium-ion batteries. Consequently, although the ZEBRA battery was used for a time in electric buses, it ultimately failed to gain widespread adoption in the electric mobility sector. 

The situation is different, however, regarding stationary applications linked to renewable energy sources. In this context, the sodium-nickel chloride energy storage system offers numerous advantages.