In Situ Prepared Three-Dimensional Covalent and Hydrogen Bond Synergistic Binder to Boost the Performance of SiO x Anodes for Lithium-Ion Batteries.

Polymer binders play an important role in enhancing the electrochemical performance of silicon-based anodes to alleviate the volume expansion for lithium-ion batteries. It is difficult for common one-dimensional (1D) linear binders to limit the volume expansion of a silicon-based electrode when combined with silicon-based particles with scant binding points. Therefore, it is necessary to design a three-dimensional (3D) network structure, which has multiple binding points with the silicon particles to dissipate the mechanical stress in the continuous charge and discharge circulation. Here, a covalent and hydrogen bond synergist 3D network green binder (poly(acrylic acid) (PAA)-dextrin 9 (Dex 9 )) was prepared by the simple in situ thermal condensation of a one-dimensional liner binder PAA and Dex in the electrode fabrication process. The optimized SiO x @PAA-Dex 9 electrode exhibits an initial Coulombic efficiency (ICE) of 82.4% at a current density of 0.2 A g -1 . At a high current density of 1 A g -1 , it retains a capacity of 607 mAh g -1 after 300 cycles, which is approximately twice as high as that of the SiO x @PAA electrode. Furthermore, the results of in situ electrochemical dilatometry (ECD) and characterization of electrode structures demonstrate that the PAA-Dex 9 binder can effectively buffer the huge volume change and maintain the integrity of the SiO x electrodes. The research overcomes the low electrochemical stability difficulty of the 3D binder and sheds light on developing the simple fabrication procedure of an electrode.