The present invention relates to the field of electrochemical technology, and in particular to a binder and a preparation method thereof and a
lithium ion battery. The preparation method comprises the following steps: mixing water, functional monomers,
styrene, electrolytes, chelating agents, and pH regulators to obtain a bottom material; mixing a cosolvent and an initiator to obtain an initiator phase; mixing butadiene,
styrene, unsaturated polyolefins, and a molecular weight
regulator to obtain an
oil phase; mixing a dispersing aid, an
electrolyte, a
functional monomer, and a cosolvent to obtain a
functional monomer phase; heating the bottom material to 40°C to 70°C, adding part of the initiator phase, reacting at a constant temperature, adding the
oil phase, the remaining initiator phase, and the
functional monomer phase, heating to 70°C to 90°C for insulation reaction, and obtaining a binder. The present invention adopts a
soap-free
emulsion polymerization method, and the prepared binder can form a good
wetting interface and bonding layer with the negative
electrode active material and the conductive agent, and form a flexible cross-linked network bonding structure with the substrate to improve the bonding force.