2.2 In-situ polymerization
Cellulose, as a natural 1D flexible material with high specific surface
area, is only used as a binder of electrochemical active substances,
which does not make full use of its surface space. Electroactive
substances such as metals, metal oxides and conductive polymers are
polymerized and deposited on the cellulose surface through in-situ
polymerization. Compared with the paper-based electrode where cellulose
is only used as the binder, this can effectively reduce the volume of
electrode material and increase the utilization rate of cellulose. In
the cellulose paper based electrode prepared by this method, cellulose
not only provides mechanical properties, but also provides an electron
transfer path for the cellulose composite fiber deposited with active
substances, which can make outstanding contributions to electrochemical
energy storage.
At present, the work of depositing active materials on cellulose surface
can be roughly divided into two types. The first is by mixing the
cellulose dispersion with the precursor of the active substance. Then
the active substance is polymerized and deposited on the surface of the
cellulose fiber to form 1D cellulose composite fiber. Finally, these 1D
composite fibers were filtered through vacuum to obtain paper based
electrodes. It should be clearly pointed out here that cellulose in the
paper-based electrode summarized in the vacuum filtration section of
this paper is only used as the binder. However, the paper based
electrode obtained by in-situ polymerization of active substances
polymerized and deposited on the cellulose surface, and then filtered by
vacuum suction, is significantly different from the previous section.
Therefore, it is necessary to classify 1D cellulose composite fibers
into a single category. The second type is to directly put the prepared
2D cellulose paper into the precursor solution of the active substance,
and directly polymerize and deposit the active substance on the 2D
cellulose paper. This section summarizes and classifies the different
loading modes of active substances in the preparation process, including
the paper based electrode based on 1D cellulose composite fiber and the
paper based composite electrode based on 2D cellulose paper. Table 2
summarizes the performance parameters of related work.
Table2 Performance parameters of cellulose paper based electrode
prepared by in-situ polymerization