Insights into Na-Ion Storage Behavior of Solid Waste-Derived Carbon via “Charge-Averaged” Discharge/Charge Voltages

We report on a simplistic procedure of converting solid waste (discarded bicycle’s rubber tube) to value-added low-dimensional carbon material, and it was used as a negative material (anode) for Na-ion battery application. A controlled oxidation route was adapted to transform rubber into concentric-shelled disordered carbon (CSC) which are quasi-spherical in morphology and consist of CSC with a semicrystalline nature. The “charge-averaged” discharge voltage and “charge-averaged” charge voltage study confirmed that the superior and stable capacity of CSC was observed for a cutoff voltage of 0.01–2.5 V in comparison with 0.01–3.0 V as the impedance-associated voltage hysteresis dominates at higher cutoff voltage. The significant increase in d-spacing of CSC (∼3.689 nm) in comparison with graphite could aid in fast sodium-ion diffusion and be able to exhibit the “specific capacity” of ∼150 mA h g–1 at a high current rate of 100 mA g–1 after 100 electrochemical cycles. This is a new approach to develop fine nanocarbon from the discarded bicycle’s rubber tube which could be investigated as a negative material for next-generation metal-ion battery applications.