Calcium ions modification polyacrylamide grafted protein binder for silicon anode in lithium-ion battery

Large volume variation in silicon anode upon (de)lithiation generally induces binding failure of binders, exaggerating further side reactions between the newly exposed surface of silicon particles and electrolyte. Herein, we greatly increase the binder binding power by lengthening the side chain of polyacrylamide (PAM) using condensation reaction with soy protein isolate (SPI) to suppress the silicon anode volume changes. This dramatically improved viscosity can deal with binding failure problems well. On this basis, stable ionic bonds are introduced into the binder by leveraging calcium ions to enhance mechanical properties . The multi-bonded binder contained stable covalent bonds , ionic bonds, and hydrogen bonds that can achieve significantly restrain the volume changes of silicon, dramatically improving the electrochemical performance , especially the cycling stability.