1. Introduction
Since the introduction of lithium-ion batteries by Sony in 1991, lithium-ion batteries have received increasing attention due to their high specific energy density and long service life. The United States, South Korea and Taiwan also focus on the development of lithium-ion batteries. In recent years, lithium secondary batteries have developed rapidly, trying to replace cadmium nickel and nickel hydride batteries, and the research and development of using polymers (polymer materials) as electrodes and electrolyte materials is particularly attractive.

2. The electrode material of the battery
2.1 Cathode material:
 · Lithium cathode material: mainly LiCoO2, LiNiO2 and LiMnO2
 · Polymer cathode material: mainly heterocyclic polymers such as polypyrrole (Ppy), polythiophene (PTh) and its derivatives
2.2 Anode material
 · Carbon material: natural graphite, coke and carbon fiber
 · Tin oxide-based anode material: a mixture containing SnO, SiO2 and a small amount of Al2O3, B2O3, P2O3, etc., gradually heated to 1000 ° C under argon atmosphere or heated for 12 h at a slightly higher temperature to obtain a mixture containing divalent tin. Oxide.

3. Electrolyte
In the last 20 years, polymer materials with high ion conductivity have received much attention. In 1973, Wright et al. first discovered that polyoxyethylene (PEO) and ionic metal salts have ionic conductivity. In 1978, Armand proposed the PEO/alkali metal salt complex as the ionic conductor of a new type of rechargeable battery with an alkali metal electrode. This proposal makes polymer solid electrolyte a hot topic in the field of polymer research for 20 years. The polymer solid electrolyte is characterized by relatively high ionic conductivity, wide potential, and easy film formation, softness, light weight, elasticity, transparency, etc. It is an inorganic glass-based solid electrolyte containing ion conductivity. Unable to achieve.
3.1 Polymer/salt complex electrolyte
Polymer solid electrolyte with PEO and lithium salt coordination
3.2 Copolymer/salt complex electrolyte
 · Random copolyether
There are two main structures: one is oxyethylene-oxymethylene structure, and the other is oxyethylene-oxypropylene (EO-PO) random copolymer.
 · Comb copolymer
Structure: The molecular weight polyether chain is grafted onto the backbone of the polymer (lower Tg)
 · Block copolymer
Structure: Oxymethylene-linked polystyrene-polyoxyethylene-polystyrene triblock polymer
 · Network structure polymer
There are two main production methods: one is to connect the polyether branch on the inorganic polymer to form a two-phase structure, that is, the inorganic support phase and the organic conductive phase; the other method is to pass the unsaturated polyether (macromonomer) Polymerization and crosslinking are carried out to form a network structure polymer electrolyte.
3.3 polymer / inorganic blend compound
Preparation of polymer-ceramic composite electrolyte by injecting inorganic particles into polymer electrolyte
3.4 Latex Particles/Salt Composite Electrolyte
Different properties of latex particles to prepare a series of two-phase polymer electrolytes, there are two ways:
A. Styrene-butadiene rubber (SBR) and butyl cyanide (NBR) latex particles!
B. Synthesis of composite latex particles with core-shell structure using rubbery and non-polar polybutadiene (PB) as the core and polar and glassy polyvinylpyrrolidone (PVP) as shells
3.5 polymer gel / salt composite electrolyte
Gel type CPE is electrolyte

4. The difference between polymer lithium ion battery and liquid lithium ion battery
The fundamental difference between a polymer lithium-ion battery and a liquid lithium-ion battery is that the electrolyte used in the two is different. The electrolyte of a lithium polymer battery is solid in appearance and is called a polymer solid electrolyte. This electrolyte is a type of polymer material which is in a solid state but which dissolves the supporting electrolyte like a liquid and can undergo ion migration.

5.The eight advantages of polymer lithium-ion batteries
5.1 Good safety performance
The polymer lithium battery is made of aluminum plastic flexible packaging, which is different from the metal outer casing of the liquid battery. Once the safety hazard occurs, the liquid battery is easy to explode, and the polymer battery core can only be air drum.
5.2 Small thickness, can be made thinner
Ordinary liquid lithium battery adopts the method of customizing the outer casing first, and then plugging the positive and negative materials. The thickness is 3.6mm or less, there is a technical bottleneck. The polymer battery core does not have this problem, and the thickness can be less than 1mm, which meets the needs of current mobile phones. direction.
The weight of the polymer battery is 40% lighter than the steel shell lithium battery of the same capacity specification, which is 20% lighter than the aluminum shell battery.
5.3 Large capacity
The polymer battery has a capacity of 10-15% higher than that of the same size steel shell battery, which is 5-10% higher than that of the aluminum shell battery. It is the first choice for color screen mobile phones and MMS mobile phones. Nowadays, the new color screen and MMS mobile phones on the market are mostly used. Polymer batteries.
5.4 small internal resistance
The internal resistance of the polymer battery core is smaller than that of the general liquid battery. At present, the internal resistance of the domestic polymer battery core can even be less than 35mΩ, which greatly reduces the self-consumption of the battery and prolongs the standby time of the mobile phone. The level of integration with the international. This polymer lithium battery that supports large discharge currents is an ideal choice for remote control models and is the most promising alternative to nickel-metal hydride batteries.
5.5 shape can be customized
Polymer batteries can increase or decrease the thickness of batteries according to customers' needs. Develop new battery models, which are cheap, open cycle is short, and some can even be customized according to the shape of mobile phones to make full use of battery casing space and upgrade batteries. capacity.
5.6 Good discharge characteristics
The polymer battery uses a colloidal electrolyte, which has a smooth discharge characteristic and a higher discharge platform than a liquid electrolyte.
5.7 The protection board is simple in design
Due to the use of polymer materials, the battery core does not ignite or explode, and the battery core itself has sufficient safety. Therefore, the protective circuit design of the polymer battery can be omitted by omitting the PTC and the fuse, thereby saving battery cost.