Research

Considerable progress made in sodium-ion batteries at Beihang University
As we know, it is inevitable that lithium supplies will run out in the foreseeable future due to the increasing demand for lithium commodity chemicals but limited lithium mineral reserves. Instead, room sodium-ion batteries have been rehighlighted for next-generation rechargeable batteries, benefiting from the abundant and inexpensive sodium resources. Recently, Associate Professor Hua Wang and Professor Lin Guo as well as their research group from school of chemistry and environmental science reported the successful fabrication of green, renewable and environment-friendly as well as ultra-fast and ultra-long life sodium-ion batteries

Confronted with environmental problem caused by waste batteries, next-generation green energy devices are urgently needed. Juglone, as a biomolecule derived from waste walnut epicarp, is first used to fabricate new composed electrodes through a facile and scalable self-assembly process directly, without any binder or additional conductive agent. The as-prepared electrodes with organic biomolecules immobilized onto reduced graphene oxide (RGO) nanosheets owing to strong intermolecular interaction between the aromatic structure and carbon scaffold, exhibit high storage capacity and cyclic stability for sodium ions storage. Furthermore, this novel method can be applied to fabricate Juglone/RGO electrodes of arbitrary size and shape with relatively high resolution and alignment accuracy on specified substrates, indicating potential applications in complex and precise fabrications of prospective biocompatible electronic devices [1]. (Adv. Mater., 2015, 27, 2348-2354.)



Figure 1: (a) Schematic diagram for the π-π interaction of Juglone molecule with RGO nanosheets, and reversible sodium-ions de/insertion mechanism as well as electron transfer of the hybridized electrodes. (b) Photographs of a flexible Juglone/RGO films on RMB coins. (c) Aluminum-pouch-type full battery used to power an electric fan.

Moreover, their group designed an ultra-fast sodium-ion battery which can fulfill a single charge in 6 min, and the specific capacity can retain 89.3% even after 10000 cycles. The presented cyclability and stability is superior to most of previous reports, and bridge the gap between traditional supercapacitors and rechargeable sodium-ion batteries. Relative results have been published in Small and reported on Materials Views[2]. (Small, 2015, 11, DOI: 10.1002/smll.201500144.)



Figure 2: Ultralong-term cycling performance of C/NTP-RT electrodes at a high current density of 10 C.

Hua Wang, associate professor, school of chemistry and environmental science, Beihang University, E-mail:wanghua8651@buaa.edu.cn

References
[1] H. Wang, P. F. Hu, J. Yang, G. M. Gong, L. Guo*, X. D. Chen, “Renewable Juglone Based High Performance Sodium-Ion Battery” Adv. Mater. 27, 2348 (2015).
[2] J. Yang, H. Wang*, P. F. Hu, J. J. Qi, L. Guo*, L. H. Wang, “A High-Rate and Ultralong-Life Sodium-Ion Battery Based on NaTi2(PO4)3 Nanocubes with Synergistic Coating of Carbon & Rutile TiO2” Small 11, doi: 10.1002/small.201500144.