With the tremendous development of renewable energies such as solar and wind powers, the smooth integration of their energies into the grid, thus improving the grid reliability and utilization, critically needs large-scale energy storage systems with low cost, long-life, high efficiency and high safety. Among the various energy storage technologies, electrochemical approach represents one of the most promising means to store the electricity in large-scale because of the flexibility, high energy conversion efficiency and simple maintenance. Due to the highest energy density among practical rechargeable batteries, lithium-ion batteries have been widely used in the portable electronic devices and would undoubtedly be the best choice for the electric vehicles. However, the rarity and non-uniform distribution of lithium in the Earth’s crust may not simultaneously support these two important application areas: electric vehicles and renewable energy. In this regard, room-temperature sodium-ion batteries with lower energy density compared with lithium-ion batteries have been reconsidered particularly for renewable energy, where cost and cycle life are more critical factors than energy density owing to the abundant sodium resources (2.75%) and low cost as well as similar “rocking-chair” sodium storage mechanism as lithium. More importantly, we can use Na⁺ions as the charge carrier to explore new chemistry and new materials to further decrease the cost. For example, sodium cannot form the alloy with aluminum, therefore aluminum foil can be used as the current collector for the anode without the overdischarge problem.

In this talk, I will present our recent research progress on the sodium-ion batteries from IoP-CAS. In particular, I will focus on a series of air-stable and Ni-/Co-free Na-Cu-Fe-Mn-O (e.g., Na_0.9Cu_0.2Fe_0.3Mn_0.5O₂) cathode and a superior low cost amorphous carbon anode made from pitch and lignin. Finally, the prototype sodium-ion batteries based on these cathode and anode materials will also be demonstrated to have promising practical application.

References:

1. Pan, H. L.; Hu, Y.-S.*; Chen, L. Q., Room-temperature stationary sodium-ion batteries for large-scale electric energy storage. Energy & Environmental Science 2013, 6, 2338-2360.

2. Sun, Y.; Zhao, L.; Pan, H. L.; Lu, X.; Gu, L.*; Hu, Y.-S.*; et al. Direct atomic-scale confirmation of three-phase storage mechanism in Li4Ti5O12 anodes for room-temperature sodium-ion batteries. Nature Communications 2013, 4, 1870.

3. Wang, Y. S.; Yu, X. Q.; Xu, S. Y.; Bai, J. M.; Xiao, R. J.*; Hu, Y.-S.*; et al. A zero-strain layered metal oxide as the negative electrode for long-life sodium-ion batteries. Nature Communications 2013, 4, 2365.

4. Xu, S.-Y.; Wu, X.-Y.; Li, Y.-M.; Hu, Y.-S.*; Chen, L.-Q., Novel copper redox-based cathode materials for room-temperature sodium-ion batteries. Chinese Physics B 2014, 23, 118202.

5. Li, Y. M.; Yang, Z.; Xu, S.; Mu, L.; Gu, L.*; Hu, Y.-S.*; Li, H.; Chen, L. Q., Air-Stable Copper-Based P2-Na_7/9Cu_2/9Fe_1/9Mn_2/3O₂ as a New Positive Electrode Material for Sodium-Ion Batteries, Advanced Science 2015, 2, 1500031.

6. Mu, L. Q.; Xu, S.; Li, Y.; Hu, Y.-S.*; Li, H.; Chen, L.; Huang, X., Prototype sodium-ion batteries using air-stable and Co/Ni-free O3-layered metal oxide cathode, Advanced Materials 2015, doi: 10.1002/adma.201502449.

7. Wang, Y.; Xiao, R.; Hu, Y.-S.*; Avdeev, M.*; Chen, L., P2-Na0.6[Cr0.6Ti0.4]O2 cation-disordered electrode for high-rate symmetric rechargeable sodium-ion batteries, Nature Communications 2015, 6, 6954.

8. Wang, Y.; Liu, J.; Lee, B.; Qiao, R.; Yang, Z.;Xu, S.;Yu, X*; Gu, L.*; Hu, Y.-S.*; et al. Ti-substituted tunnel-type Na_0.44MnO₂ oxide as a negative electrode for aqueous sodium-ion batteries. Nature Communications 2015, 6, 6401.

9. Wang, Y.; Mu, L. Q.; Liu, J.; Yang, Z.; Xu, S.; Yu, X.*; Gu, L.*; Hu, Y.-S.*; Li, H.; Yang, X.-Q.; Chen, L.; Huang, X., A novel high capacity positive electrode material with tunnel-type structure for aqueous sodium-ion batteries, Advanced Energy Materials 2015, doi: 10.1002/aenm.201501005.

10. Xu, S.; Wang, Y.; Ben, L; Lyu, Y.; Song, N.; Yang, Z.; Li, Y.; Mu, L. Q.; Yang, H. T.*; Gu, L.*; Hu, Y.-S.*; et al. Fe-based Tunnel-type Na_0.61[Mn_0.27Fe_0.34Ti_0.39]O₂ Designed by A New Strategy as Cathode Material for Sodium-ion Batteries, Advanced Energy Materials 2015, doi: 10.1002/aenm.201501156.

11. Wu, X. Y.; Jin, S. F.; Zhang, Z. Z.; Jiang, L. W.; Mu, L. Q.; Hu, Y.-S.*; Li, H.; Chen, X. L.; Armand, M.; Chen, L.; Huang, X., Unravelling the storage mechanism in organic carbonyl electrodes for sodium-ion batteries, Science Advances 2015, 1, e1500330.

12. Li, Y.; Mu, L.; Hu, Y.-S.*; Li, H.; Chen, L.; Huang, X., Pitch-derived amorphous carbon as high performance anode for sodium-ion batteries, Energy Storage Materials 2015, doi: 10.1016/j.ensm.2015.10.003.

13. Li, Y.; Hu, Y.-S.*; Li, H.; Chen, L.; Huang, X., A superior low-cost amorphous carbon anode made from pitch and lignin for sodium-ion batteries, Journal of Materials Chemistry A 2015, doi: 10.1039/C5TA08601A.