A conductive self-healing hydrogel binder for high-performance silicon anodes in lithium-ion batteries

Abstract

Although silicon has been viewed as the ideal anode material due to its superior specific capacity, silicon materials easily break down because of its large volume changes during frequent charge-discharge cycles. Polymeric binders play key roles on maintaining the mechanical integrity of electrodes and contributing substantially to improving cycle lives. Here, we design and prepare that a novel conductive self-healing hydrogel (ESVCA) binder with 3D conductive network, excellent stretchablity and fast self-healing ability coating on the surface the Si particle by in-situ polymerization method. The stretchable 3D self-healable network structure could effectively restrain the huge volume change of Si particles during lithiation and delithiation cycles to maintain mechanical integrity of the Si electrodes while 3D continuous electron transport pathways insuring the high conductivities and better electric contacts among active Si particles. The Si-ESVCA electrode not only exhibits a reversible capacity of 1786 mA h g−1 at 500 mA g−1 with a capacity retention of 71.3% after 200 cycles at ambient temperature, but also maintains superior cycling stability with a capacity retention of 74.1% and remains a high reversible capacity of 1743 mA h g−1 after 200 cycles at current density of 2000 mA g−1 at elevated temperature.