Novel silicon nanoparticles-based carbonized polypyrrole nanotube composites as anode materials for Li-ion batteries

Abstract

The development of elastic nanostructured Si-based anodes holds promise for advancing lithium-ion batteries due to the high theoretical specific capacity exhibited by Si. Combining nanostructured Si with C proves to be a successful strategy in addressing the challenges tied to the substantial volume expansion of Si during lithiation. In this work, a novel Si-based anode is fashioned through a simple and universal strategy, integrating Si nanoparticles with 1D nano-carbonaceous fillers (CPPy-NT) featuring nanotubular morphology and N atoms, and a water-based binder (poly(acrylic acid)). CPPy-NT are derived by carbonizing pre-synthesized polypyrrole nanotubes (PPy-NT). A clear correlation is established among the carbonization temperature for CPPy-NT preparation, N content in CPPy-NT, electrical conductivity, and the electrochemical performance of the ensuing Si/CPPy-NT anode. For comparative analysis, the electrochemical properties of the Si-based anode employing Super P (commercial carbon black) or PPy-NT are contrasted with those of Si/CPPy-NT. Notably, the Si/CPPy-NT anode with CPPy-NT bearing the highest amount of graphitic N sites exhibits a substantial improvement in initial charge capacity (approximately 2200 mAh g−1) and enhanced cycling stability. These findings underscore the potential to elevate the electrochemical activity of the C filler by carefully optimizing morphology, conductivity, and the incorporation of an appropriate amount of graphitic N.