Pencil lead powder as a cost-effective and high-performance graphite-silica composite anode for high performance lithium-ion batteries

Abstract

A facile method has been demonstrated in this research to prepare a graphite/silica composite anode from pencil needle powder. The obtained pencil needle powder is well characterized using X-ray diffraction, Raman spectroscopy, field emission scanning electron microscope, and high-resolution transmission electron microscope. The 4B pencil lead electrode outperformed graphite delivering a high specific capacity of 501 mAh g−1 after 100 cycles of galvanostatic charge-discharge at 100 mAg−1 current density. Further, the material has shown excellent specific capacities at various current densities. Furthermore, we elucidated the reaction mechanism taking place at the pencil electrode interface with density functional theory and post SEM and EDX analysis of the electrode. The outstanding anode performance is mainly due to the synergy of graphite/SiO2 composite where silica is also being converted to a stable fluorinated solid electrolyte interface (SEI) on the electrode surface. To check the commercial applicability of the inexpensive electrode, a comparative study has been made with commercially available cathodes like lithium iron phosphate (LFP) and lithium nickel manganese cobalt oxide (NMC). Excellent cyclic stability with high discharge capacities observed during galvanostatic charge-discharge confirms the potential use of such electrodes for high performance and low-cost Li-ion batteries.