Ni5O4

Ni₅O₄ is a nickel oxide ceramic compound that exists as a mixed-valence nickel oxide, part of the broader family of transition metal oxides used in electrochemistry and materials science. This material has attracted research attention primarily in energy storage and catalytic applications, where its variable oxidation states and ionic conductivity make it potentially useful for battery electrodes and electrocatalysis, though it remains less widely deployed industrially than simpler nickel oxide phases like NiO.