Three-Dimensional Conductive Gel Network as an Effective Binder for High-Performance Si Electrodes in Lithium-Ion Batteries.

Silicon (Si) has been widely investigated as a candidate for lithium-ion batteries (LIBs) due to its extremely high specific capacity. The binders play a key role in fabricating high-performance Si electrodes which usually suffer from the huge volume expansion associated with the alloying and dealloying processes. Here we develop a facile route to prepare a three-dimensional (3D) conductive interpenetrated gel network as a novel binder for high-performance Si anodes through chemically cross-linking of acrylic acid monomer followed by the in situ polymerization of aniline. The excellent electrical conductivity, strong mechanical adhesion and high electrolyte uptake render the conductive gel network a potential binder for high-performance Si anodes. The resultant Si anodes exhibit excellent cycling stability, high Coulombic efficiency and superior rate capability, revealing better electrochemical properties compared to the Si anodes with conventional binders. The 3D conductive gel binder could not only accommodate the volume expansion and maintain electric connectivity, but also assist in the formation of stable solid electrolyte interphase (SEI) films. Such a strategy sheds light on the design of polymer binders in LIBs, especially for high-capacity electrode materials with huge volume changes during long-term cycling.