Enhancing the electrochemical performances of silicon-dominant anodes for Li-ion batteries using Li-doped polyaniline coating

Abstract

Silicon is the promising anode material for next-generation Li-ion batteries, because it has the highest theoretical capacity (4200 mAh g-1) as well as it is abundant and hence cost-effective. However, it experiences a severe volume change (~ 400 %) during dis/charge, thus each silicon particles cracks and loses their electrical connection to the current collector leading to severe capacity decay1 . Polyaniline is not only a conductive polymer but also an appropriate coating material for the silicon nanoparticles2 . Moreover, the nature of the polyaniline is easily adjusted by altering its doping materials in the emeraldine salt form. Co-doping of lithium in an emeraldine salt makes the polyaniline＆rsquo;s electrical conductivity high as reported in the previous study3 . On the basis of these studies, we assumed that lithium-doped polyaniline coating could enhance silicon anodes for Li-ion batteries. Herein, we synthesized the Li-doped polyaniline coated silicon. anode via in situ chemical oxidative method, and conducted the rate capability test, cycle stability test, and EIS (electrochemical impedance spectroscopy) using the Li-ion half-cells employing the as-prepared anode. As a result, the Li-doped polyaniline-coated silicon showed higher electrochemical performances than the pristine polyaniline coated silicon.