Silicon has been focused as a promising anode material due to its high theoretical capacity (3579 mAh g-1). However, it suffers from capacity degradation due to the evolution of fractures in the electrode caused by the volume expansion of Si (~300%) during cycling . To overcome this problem, water-soluble polymers have been suggested as alternatives of a traditional PVDF-binder system for improving the mechanical stability and electrochemical properties of Si through their strong interaction capabilities between active materials and binder [2-4]. Herein, we first introduce the polyacrylamide (PAM) hydrogel as a new binder system, which has a good capacity for preserving their mechanical strength and shape with abundant polar-functional groups in their structure. For the 3D-polymer network in the electrode, we applied in situ polymerization method during the electrode fabrication. Through this 3D PAM network, the composite electrode exhibited a great capacity retention of ~2000 mAh g-1 after 300 cycles. Accordingly, the effect of the chemical/mechanical properties of PAM gel on the electrochemical properties of Si is adequately elucidated, and these results are properly applied for the design as a novel binder system in the Si anode.
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