In recent years, lithium - ion batteries have been developing rapidly. Their applications have expanded from mobile phones and laptops to fields such as electric vehicles and energy storage systems. The rapid development of lithium - ion batteries has put forward new requirements in terms of large - scale technology, high energy surface density, fast charging and discharging, cycle stability, environmental protection, and safety.

Adhesives are non - active substances in the positive and negative electrode materials, but they have a significant impact on the overall performance of lithium - ion batteries. Generally, the amount of adhesives used accounts for 2 - 5% of the total battery materials, and the cost accounts for less than 1% of the battery manufacturing cost. However, they can improve the battery performance by 5 - 10%, making them one of the essential materials in lithium - ion battery production. Their main function is to connect the electrode active materials, conductive agents, and electrode current collectors, enabling integral connectivity among the electrode active materials, conductive agents, and current collectors, thereby reducing the impedance of the electrode.

The requirements for adhesives in lithium - ion batteries are different from those of ordinary adhesives. They mainly include: (1) good electrochemical stability; (2) resistance to electrolyte corrosion; (3) good solubility in certain solvents; (4) good bonding performance to metals; (5) relatively good flexibility. Currently, the mainly applied adhesive is the solvent - based PVDF (polyvinylidene fluoride) adhesive with NMP (N - methylpyrrolidone) as the dispersant. In battery applications, PVDF adhesives have exposed some drawbacks. Their relatively high elastic modulus (1 - 4 GPa) results in insufficient toughness of the electrode sheets. They have certain swelling in the used electrolyte, are insulative to particles and electrons, and will increase the internal resistance of the battery. In addition, the NMP dispersant is expensive, has a high volatilization temperature, requires a large amount of use, has a high recovery cost, and is harmful to human health. Therefore, the selection of water - based adhesives with water as the dispersion medium for lithium - ion negative electrode materials has become the mainstream direction.