The transport properties of sodium-ion in the low potential platform region of oatmeal-derived hard carbon for sodium-ion batteries

Hard carbon is the most common carbon-based material with abundant raw material resources, low cost, high reversible capacity and reliable safety performance, it is the most suitable sodium-ion batteries (SIBs) anode material for commercial production, which attracts the interest of the researchers. Unfortunately, the electrochemical performances of hard carbon are still underestimated in the previous reports. In this research, we use a simple process flow to obtain carbonized oatmeal as a kind of hard carbon. It can deliver initial reversible capacity of 272.4 mAh g−1 at 20 mA g−1, the capacity retention rate is 93.3% after 100 cycles, exhibits a good electrochemical performance. Simultaneously, the transport properties of sodium-ion in carbonized oatmeal material are also characterized by electrochemical impedance spectroscopy (EIS) and galvanostatic intermittent titration technique (GITT). The measurement results show that the low potential platform region of the oatmeal-derived hard carbon is attributed to the insertion/extraction characteristics of sodium-ion in the graphitic microcrystallites sheets.