Carbon nanoparticle-based three-dimensional binder-free anode for rechargeable alkali-ion batteries

Abstract

We demonstrate a simple and effective method for the fabrication of three-dimensional (3D) binder-free carbon anode using biomass as a carbon source. The anode consisted of interconnected carbon nanoparticles self-assembled onto a nickel foam substrate, providing easy electrolyte access throughout the electrode. The unique 3D electrode architecture prevented deformation of the electrode during cycling. The absence of binder and conducting additive simplifies the electrode fabrication process, thus lowering the battery fabrication costs. As a proof of concept, the anode when tested against lithium delivered a specific discharge capacity of 764 mA h g−1 at a current density of 50 mA g−1, with an exceptional cycling stability at high current rates (e.g., delivering a capacity of 664 mA h g−1 at 500th cycle at a current density of 1 A g−1). Furthermore, the anode was also tested against sodium, exhibiting a reversible discharge capacity of 241 mA h g−1 in the second cycle at a current density of 50 mA g−1 and remained stable over prolonged cycling. The ion storage mechanism was studied using ex-situ spectroscopic techniques.