A Robust Ion-Conductive Biopolymer as a Binder for Si Anodes of Lithium-Ion Batteries

• Published in: Advanced functional materials Vol. 25; no. 23; pp. 3599 - 3605
• Main Authors: Liu, Jie, Zhang, Qian, Zhang, Tao, Li, Jun-Tao, Huang, Ling, Sun, Shi-Gang
• Format: Journal Article
• Language: English
• Published: Blackwell Publishing Ltd 01.06.2015
• Subjects: Anodes; Binders; biopolymers; Guar gum; Hydroxyl groups; ion-conductivity; Lithium ions; Lithium-ion batteries; Nanostructure; Silicon; silicon anodes
• ISSN: 1616-301X; 1616-3028
• DOI: 10.1002/adfm.201500589

Binders have been reported to play a key role in improving the cycle performance of Si anode materials of lithium‐ion batteries. In this study, the biopolymer guar gum (GG) is applied as the binder for a silicon nano­particle (SiNP) anode of a lithium‐ion battery for the first time. Due to the large number of polar hydroxyl groups in the GG molecule, a robust interaction between the GG binder and the SiNPs is achieved, resulting in a stable Si anode during cycling. More specifically, the GG binder can effectively transfer lithium ions to the Si surface, similarly to polyethylene oxide solid electrolytes. When GG is used as a binder, the SiNP anode can deliver an initial discharge capacity as high as 3364 mAh g−1, with a Coulombic efficiency of 88.3% at the current density of 2100 mA g−1, and maintain a capacity of 1561 mAh g−1 after 300 cycles. The study shows that the electrochemical performance of the SiNP anode with GG binder is significantly improved compared to that of a SiNP anode with a sodium alginate binder, and it demonstrates that GG is a promising binder for Si anodes of lithium‐ion batteries. Guar gum is used as a robust binder for a silicon nanoparticle anode of a lithium‐ion battery for the first time. With a large number of polar hydroxyl groups, the guar gum binder can provide effective transport pathways for lithium ions, which significantly improves the electrochemical performance.