The invention discloses a mercury-free button
cell cathode cap material and a preparation method thereof, and belongs to the field of a mercury-free alkaline
zinc-
manganese button
cell. The preparation method comprises the following steps: by taking a steel strip as a base, arranging a
nickel coating on one side of the base as the external surface of a
cell cathode cap, and orderly electrically depositing the
nickel coating, a
copper coating, a first
zinc coating, a
tin coating, an
indium coating and a second
zinc coating on the other side of the base; and thermal treating all the
metal coatings to improve the
toughness of the outermost zinc coating, wherein the
tin coating and the
indium coating are protected by the arrangement of the inner and outer zinc coatings, and a
tin diffusion layer, an
indium diffusion layer and a
zinc diffusion layer are formed, thus the
hydrogen evolution over-potential is increased; and by mechanical rolling, the
stamping resistance of a product is effectively improved. Compared with a conventional process for directly preparing an
alloy, the
cathode cap material prepared by the method disclosed by the invention is simpler and easier to operate, effectively prevents the problems that the tin coating falls off and is adhered with a
grinding tool during the preparation of a cathode cap by use of an original pre-coating method, simultaneously realizes an aim of
environmental protection by replacing mercury with indium, has good
stamping performance and air expansion resistance, can completely realize no use of mercury of the alkaline zinc-
manganese button cell and is applicable to industrial production.