Central South University: Graphene helps enhance the performance of rapid sodium storage

Sodium-ion batteries (SIBs) have become the most promising new energy storage devices to replace lithium-ion batteries with their lower cost

Recently, Professor Zhang Jiafeng from Central South University and his team conducted an in-depth exploration of the layered induction structure between the active material and the carbon material based on the energy band theory, proving that the bond between the metal and the carbon plays a key role in the good sodium storage performance of the material

Different from other methods to obtain high energy density by designing new materials or battery systems, SIBs currently urgently need to maximize the potential of electrode materials

In response to this problem, the author of this paper took GeS ₂ and graphene as the research object, and conducted a study on the relationship between the three contact modes of GeS ₂ /C composite phase, CS bond and C-Ge bond and reactive potential and polarization potential.

Figure 1 Schematic diagram of electron/ion transfer in SIBs of the three models of GeS ₂ /C composite phase, CS bond and C-Ge bond

Figure 2 Schematic diagram of the preparation of GeS ₂ /3DG and electron microscopy characterization analysis

Figure 3 Analysis of the structure and chemical state of the sample

Figure 4 Reaction kinetic analysis of samples and calculation of pseudocapacitance contribution ratio

Figure 5 Characterization of structural changes during charge and discharge

Figure 6 Sample sodium storage performance test

In general, the authors found that graphene not only uses C-Ge bonds as active sites, but also provides an additional ion transport channel for GeS ₂