From past few years, the investigations on the sodium-ion batteries (NIBs) have increased substantially due to its advantages and prospect benefits in the large-scale energy storage systems. Though, the energy density of the NIB is a challenge; thus, the application of NIBs for commercial uptake is delaying.
Also, hard carbon is also the promising anodes in the NIBs due to their good performance such as the high capacity of about 330 mAh g-1, good stability, high Coulombic efficiency, and cost-effectiveness.
Extensive efforts are dedicated to the development of high-performance anode of carbon material with consistent discharge behavior are represented in two distinct regions. These regions exhibit higher capacity than slope region and higher capacity than carbon anode. This can further increase the density of cell in positions of average voltage. Therefore, designing carbon anode with a large amount of the table capacity can be potential to the increased density of these NIBs.
Prof. Yong-Sheng Hu working at the Institute of Physics, the Chinese Academy of Sciences reported the structure like bi-honeycomb by carbonizing specific type of charcoal at high temperature. This anode of carbon has a capacity of nearly 400 mAh g-1, which higher than hard carbon material. About 85% of this capacity results from the long low-potential table is near about 0.1 V which varies from the curves of hard carbon of NIBs.
When this hard carbon is mixed with air-stable Na0.9Cu0.22Fe0.30Mn0.48O2 as a layered cathode which has a high density of energy nearly 240 Wh kg-1 with good capability and stability. This detection of the promising anode of the carbon material is expected to conduct upgraded density NIBs in the high-scale energy storage.