The invention provides wood-based carbon foam and a preparation method thereof, a
cathode electrocatalyst, a
cathode and a
metal-air battery, and relates to the technical field of batteries. The preparation method comprises the following steps: mixing
lignin-removed wood with a first solution, carrying out
solid-liquid separation to obtain a wood precursor, then removing air in the wood precursor, carrying out low-temperature curing and
freeze drying to obtain wood-based foam, and pyrolyzing the wood-based foam in an
inert atmosphere to obtain wood-based carbon foam; wherein the wood subjected to
lignin removal has a certain
porosity, meanwhile, the original
structural property of the wood can be kept,
transition metal salt and
heteroatom compounds can conveniently enter pore channels of the wood, and subsequent
doping of the
transition metal salt and the
heteroatom compounds is facilitated; furthermore, the graphitization degree of the wood-based carbon foam can be improved by adding the
transition metal, so that the electro-catalytic performance of the wood-based carbon foam is improved; and by adding the
nitrogen-containing compound, the structure of the wood-based carbon foam is effectively changed, the alkaline site on the surface of the wood-based carbon foam is increased, the hydrophilicity of the wood-based carbon foam is enhanced, and the wood-based carbon foam shows electro-catalytic performance.