Tailoring sodium intercalation in graphite for high energy and power sodium ion batteries

• Published in: Nature communications Vol. 10; no. 1; pp. 2598 - 10
• Main Authors: Xu, Zheng-Long, Yoon, Gabin, Park, Kyu-Young, Park, Hyeokjun, Tamwattana, Orapa, Joo Kim, Sung, Seong, Won Mo, Kang, Kisuk
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 13-06-2019; Nature Publishing Group; Nature Portfolio
• Subjects: 140/131; 140/133; 639/4077; 639/4077/4079; 704/172; Anodes; Batteries; Cathodes; Electric potential; Electrolytes; Electrolytic cells; Energy storage; Feasibility studies; Flux density; Graphite; Humanities and Social Sciences; Intercalation; Intercalation compounds; multidisciplinary; Rechargeable batteries; Science; Science (multidisciplinary); Sodium; Sodium channels (voltage-gated); Sodium-ion batteries; Storage systems; Temperature dependence
• ISSN: 2041-1723; 2041-1723
• DOI: 10.1038/s41467-019-10551-z

Co-intercalation reactions make graphite as promising anodes for sodium ion batteries, however, the high redox potentials significantly lower the energy density. Herein, we investigate the factors that influence the co-intercalation potential of graphite and find that the tuning of the voltage as large as 0.38 V is achievable by adjusting the relative stability of ternary graphite intercalation compounds and the solvent activity in electrolytes. The feasibility of graphite anode in sodium ion batteries is confirmed in conjunction with Na
1.5
VPO
4.8
F
0.7
cathodes by using the optimal electrolyte. The sodium ion battery delivers an improved voltage of 3.1 V, a high power density of 3863 W kg
−1
both electrodes
, negligible temperature dependency of energy/power densities and an extremely low capacity fading rate of 0.007% per cycle over 1000 cycles, which are among the best thus far reported for sodium ion full cells, making it a competitive choice in large-scale energy storage systems.
Graphite is a promising anode material for sodium-ion batteries but suffers from the high co-intercalation potential. Here, the authors examine the factors influencing this potential and tailor the stability of graphite intercalation compound, realizing high energy and power densities.