Investigation into Durable Polymers with Enhanced Toughness and Elasticity for Application in Flexible Li-Ion Batteries

Abstract

Next-generation wearable devices compel the development of lithium-ion batteries (LIBs) that can afford mechanical flexibility while remaining safe and stable energy sources. In conventional battery designs the electrode coatings are susceptible to fracture and disintegration when exposed to cyclic flexure. This results in capacity loss, resistance increases, and severely limits their cycle life. Polyurethane (PU) has been investigated as a battery binder but without research into the variety of chemistries available, and how they affect performance. This research investigates three different PU chemistries, each composed of a different polyol backbone–polyester, polyether and polycaprolactone. These are compared with PVDF, the most commonly used rigid binder in industry. The combination of electrochemical and mechanical characterization identified the importance of PU binder chemistry, particularly when the binder’s interaction with the electrolyte was considered. Both the polyester and polycaprolactone PU chemistries swelled significantly when placed in an electrolyte, compromising their conductive networks and mechanical advantages. In contrast, polyether PU was found to be a suitable binder for flexible batteries as it has strong adhesion and retains its properties even after swelling in the electrolyte. These findings present a promising polymer choice to facilitate the development of advanced and durable electrodes for flexible energy storage systems.

Epoxy Cross-Linking Enhanced the Toughness of Polysaccharides as a Silicon Anode Binder for Lithium-Ion Batteries

“…Many researchers have confirmed that an appropriate binder in the electrolyte is conducive to the transmission of ions and electrons. 45 Based on this, the following experiment was carried out: The SH and SH-ECH films of equal masses and sizes were placed into beakers containing the same volume of electrolyte. The films were taken out after the same amount of time.…”

“…The contact angles on the SH and SH-ECH films both became 0 after 1 s, which indicated a good affinity between the electrolyte and the binders. Many researchers have confirmed that an appropriate binder in the electrolyte is conducive to the transmission of ions and electrons . Based on this, the following experiment was carried out: The SH and SH-ECH films of equal masses and sizes were placed into beakers containing the same volume of electrolyte.…”

Microbial-Copolyester-Based Eco-Friendly Binder for Lithium-Ion Battery Electrodes

“…The binder physically stabilizes the electrode and plays a key role in improving the energy density and controlling the long-term cycling stability by maintaining the durability of the electrode through the adhesion between the particles. Therefore, the stability of the secondary battery upon prolonged cycling can be maintained by understanding the role of the binder and improving its performance. − The binder must be electrochemically stable because it is subjected to a wide voltage range during charging and discharging. Hence, it should allow the maintenance of the electrode structure without undergoing additional oxidation or reduction, in addition to the active material, during charging and discharging.…”

Switchable Copolymerization of Maleic Anhydride/Epoxides/Lactide Mixtures: A Straightforward Approach to Block Copolymers with Unsaturated Polyester Sequences

“…They have wide applications in biomedical fields, [1][2][3][4] sustainable plastics/elastomer, [5][6][7][8][9][10][11][12] and solid electrolytes [13,14] or DOI: 10.1002/macp.202200079 electrode binders. [15] Among various copolymers, block copolyesters can combine the properties of the respective homopolymers to furnish a new set of functionalities and exhibited adjustable and extensive macroscopic properties because of the block incompatibility. [16][17][18][19][20][21][22][23][24] Especially, block copolymers with highly reactive maleate or fumarate sequences in backbone enables further enhancement of polymer properties through post-polymerization modifications, and thus have attracted increasing attentions in recent years.…”