Two research teams respectively led by XJTU Prof. Li Jv from the Frontier Institute of Science and Technology, and Researcher HuYongsheng from the Institute of Physics of the Chinese Academy of Sciences, found that the traditional half-cell research method substantially underestimates the performance of hard carbon negative electrodes. They therefore devised an improved plan for evaluating hard carbon performances.

The newly developed hard carbon, named as MHC, was derived from macadamia shell by pyrolysis, and it can deliver a specific capacity of 314mAh/g and a high initial Coulombic efficiency of 91.4%, proving that this hard carbon material has the highest initial Coulumbic efficiency ever reported. Combined with NCNFM anode material, the rate capability of the primary cell far exceeded that of the half-cell, and the capacity retention ratio was above 70% even after circulation of 1300 times under the magnification of 1C. The results changed people's understanding about the rate capability and cycling stability of the sodium-ion battery hard carbon anode material. This should not only exert great influence on the development of sodium-ion battery, but also promote the industrialized transformation of the sodium ion battery from research to practice.