The research shows that the internal resistance of fiber lithium ion battery changes with length, which provides effective solutions for interface stability between active materials and fiber electrode, and promotes the development of a new type of fiber polymer lithium ion battery equipped with good safety and comprehensive electrochemical performance.

Based on the research results, the fiber polymer lithium ion battery, at a length of 1m, can effectively charge wearable electronic devices for a long time including smart phones, bracelets and heart rate monitors. Simultaneously, with good cycle stability, the battery capacity retention rate still reaches 90.5% after 500 cycles; In view of 1 cm radius of curvature, the battery capacity retention rate is still over 80% with being bent 100,000 times.

"Like woolen yarn, enough wool is needed to weave a rechargeable sweater." Peng's team members found that it is necessary to clarify the relationship between internal resistance and length of fiber batteries from the origin, so as to achieve the continuous construction of fiber lithium ion battery. With great efforts to fiber current collectors with different electrical properties, they finally found a law that the internal resistance of fiber lithium ion battery decreased with increased length and then gradually kept stable, which provided a strong theoretical support for the continuous construction of fiber lithium ion batteries.

In doing so, it is important to realize the efficient and continuous preparation of active materials for fiber lithium ion battery with efficient load. "The best way is surface coating, but it is easy to form a rough beaded structure on the fiber surface coated, leading to some impacts on the performance and stability of the battery." He Jiqing said, a doctoral student in the Department of Macromolecular Science of Fudan University.

Therefore, a new method was made. Interface stability of polymer composite active material and conductive fiber current collectors can be solved effectively by adjusting and controlling the composition and adhesion of positive and negative active materials, which produces positive and negative fiber electrode materials with high load, proportioned coating and matched capacity. Then, a series of methodology-based researches are carried out by the team to focus on continuous assembly and packaging of batteries, and they develop the continuous and stable preparation of fiber polymer lithium ion battery with high performance. According to the report, we know that the team has produced large-scale battery fabrics with great performance based on textile methods. The battery fabric and wireless charging transmitter are integrated to charge the smart phone in a safe, stable and wireless mode.

"Compared with the energy density of flat battery for common use, there are considerable promotion potential for fiber lithium polymer ion battery with a broad prospect. In addition, the advanced weaving technology weaving batteries into various clothes provides a comfortable experience for people." Peng said.

Source: Textile fabric platform