Water-based electrode binder for sulfur positive electrode and preparation method thereof

Abstract

The invention discloses a water-based electrode bonding agent for a sulfur positive pole and a preparing method. The water-based electrode bonding agent for the sulfur positive pole is butyl acrylate / styrene segmented copolymer rubber latex, the structure expression formula is R-AAn1-b-Stn2-b-BAn3-b-Stn4-b-BAn5-b-Stn6-X, the segmented copolymer is stably dispersed in water in a particle mode to form the rubber latex, and the average diameter of particles is about 98 nm to 147 nm. The water-based bonding agent prepared with the method applied to the sulfur positive pole has the advantages of being high in specific capacity and good in cycle performance, the specific discharging capacity can be 935.7 mAh / g after the water-based electrode bonding agent is cycled 50 times at 0.2 C multiplying power, the bonding agent is good in preparing controllability, the preparing technology is simple, the process is environmentally friendly, energy is saved, and raw materials are low in cost and easy to obtain.

Description

technical field [0001] The invention belongs to the field of polymer material technology and lithium-sulfur batteries, and in particular relates to a water-based electrode binder and a preparation method. Background technique [0002] The low energy density of batteries is one of the main problems faced by current lithium-ion battery applications. Compared with the energy density of negative electrode graphite of 347mAh / g, the energy density of commonly used positive electrode ternary materials and lithium iron phosphate is less than 200mAh / g. Therefore, the development of high energy density positive electrode materials is the key to solving the current low energy density of lithium-ion batteries. question. Using sulfur as the positive electrode material, its specific capacity can reach 1672mAh / g, and the theoretical specific energy of the obtained lithium-sulfur battery can reach 2600wh / kg. In addition, the active material sulfur is naturally abundant, cheap, and environ...

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Problems solved by technology

However, it is easy to swell in the electrolyte and gel to form a viscous liquid, so that the electrode particles fall off, the conductive network collapses, and high interface resistance occurs.

At the same time, the use of polyvinylidene fluoride corresponding solvent N-methylpyrrolidone (NMP) has a high boiling point (203°C), is expensive, and is toxic. The high boiling point requires a longer drying time and a higher drying temperature (80°C) Volatilization, which will cause loss of active substance

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