The invention discloses a
cellulose paper-based diaphragm for a
zinc-
iodine battery as well as a preparation method and application of the
cellulose paper-based diaphragm. The diaphragm is of a three-layer
composite structure and comprises a matrix layer formed by paper pulp fibers such as
softwood pulp,
hardwood pulp, bamboo pulp or
straw pulp through a wet
papermaking technology, and compact functional
layers which cover the two sides of the matrix layer and are formed by oxidized
nanocellulose (TOCN). The preparation method mainly comprises the following steps: preparing the paper-based diaphragm matrix through wet
papermaking,
coating the two sides of the paper-based diaphragm matrix with TOCN
aqueous dispersion, and finally carrying out hot-pressing
drying treatment to enable the three
layers to be tightly combined. According to the invention, the nano aperture and the surface negative
electricity functional group of the TOCN layer are utilized, so that physical blocking and electrostatic repulsion of polyiodide ions can be realized at the same time, and the shuttle effect is effectively inhibited; and the uniform pore channels can guide
zinc ions to uniformly deposit and inhibit dendritic
crystal growth. The diaphragm is green in
raw material, simple in process and low in cost, and the cycle life and coulombic efficiency of the battery can be remarkably improved when the diaphragm is applied to the
zinc-
iodine battery.