Novel D-Glucose Derived Hard Carbon Anode for Sodium-Ion Batteries
Authors: Väli Ronald , Tooming Tauno , Thomberg Thomas , Jänes Alar , Lust Enn 
Published: February 2020

The synthesis and characterization of a hard carbon anode material for room-temperature sodium-ion battery is being reported. The carbon material was prepared via two-step process including hydrothermal carbonization (HTC) and pyrolysis. Similar carbon materials were recently synthesized and investigated by our group as supercapacitor electrode materials [1,2]. Sodium-ion batteries have emerged as a promising candidate for large-scale energy storage due to sodium’s abundance and low cost of raw materials. However, significant work is needed on the development of Na-ion intercalation anodes [3,4].

The materials were investigated using SEM, HR-TEM, gas sorption techniques and Raman spectroscopy. Electrochemical characterization has been carried out using cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) and galvanostatic charge/discharge method (GCD).

The glucose derived carbon particles have a round shape and consist of both ordered and disordered graphitic domains, as can be seen from HR-TEM images (Figure 1a).

The electrode slurry was prepared by mixing the carbon active material, conductive additive (Super P) and polyvinylidene difluoride (PVdF) binder in a 75:15:10 mass ratio. The mixed slurry was cast onto copper foil using doctor-blade technique. The cast electrodes were dried under vacuum for 24h. The half-cells (EL-Cell GmbH) were assembled in an Argon-filled glovebox (O2 < 0.1 ppm, H2O < 0.1 ppm). Sodium metal was used as counter and reference electrode and 1M NaClO4 in propylene carbonate (PC) as the electrolyte.

Cyclic voltammograms measured at 0.5 mV s-1 potential scan rate are shown in Figure 1b. The identical shape of the CVs indicates good reversibility. Very well developed peaks at E = 10 mV and E = 100 mV suggest that reversible Na-ion intercalation is taking place in the material. However, the electrode seems to exhibit some capacitive properties in the potential region from 225 mV to 1 V, after which the current density drops suggesting that the electrode is charged positively and therefore Na-ions are replaced by bigger and more solvated ClO4
- anions. Galvanostatic charge-discharge curves in Figure 1c show discharge capacity values of 250 mAh g-1 at 50 mA g-1 current density. The half-cells were cycled between 0.005 and 1.5 V vs Na/Na+.

The effect of co-intercalating solvents [5–8] will be analysed using electrochemical techniques together with ex situ/in situ Raman spectroscopy data.

Acknowledgements

The present study was supported by the Estonian Centre of Excellence in Science project 3.2.0101.11-0030, Estonian Energy Technology Program project 3.2.0501.10-0015, Material Technology Program project 3.2.1101.12-0019, Project of European Structure Funds 3.2.0601.11-0001, Estonian target research project IUT20–13, NAMUR project 3.2.0304.12-0397 and projects 3.2.0302.10-0169 and 3.2.0302.10-0165.

References

1. T. Tooming, T. Thomberg, H. Kurig, A. Jänes, and E. Lust, J. Power Sources, 280, 667 (2015).

2. T. Thomberg, T. Tooming, T. Romann, R. Palm, A. Jänes, and E. Lust, J. Electrochem. Soc., 160, A1834 (2013).

3. N. Yabuuchi, K. Kubota, M. Dahbi, and S. Komaba, Chem. Rev., 114, 11636 (2014).

4. M. D. Slater, D. Kim, E. Lee, and C. S. Johnson, Adv. Funct. Mater., 23, 947 (2013).

5. R. Alcántara, P. Lavela, G. F. Ortiz, and J. L. Tirado, Electrochem. Solid-State Lett., 8, A222 (2005).

6. O. Tanaike and M. Inagaki, Carbon, 37, 1759 (1999).

7. A. Ponrouch, E. Marchante, M. Courty, J.-M. Tarascon, and M. R. Palacín, Energy Environ. Sci., 5, 8572 (2012).

8. H. Kim, J. Hong, G. Yoon, H. Kim, K.-Y. Park, M.-S. Park, W.-S. Yoon, and K. Kang, Energy Environ. Sci., 8, 2963 (2015).

Figure 1