| Affiliation: | 1. College of Light-Textile Engineering and Art, Anhui Agriculture University, Hefei, 230036 P. R. China
Institute of Physics and Macro- and Nanotechnologies MacroNano (IMN & ZIK), Ilmenau University of Technology, 98693 Ilmenau, Germany;2. Hefei National Laboratory for Physical Sciences at the Microscale, School of Chemistry and Materials Science, University of Science and Technology of China, Hefei, Anhui, 230026 P. R. China;3. Institute of Physics and Macro- and Nanotechnologies MacroNano (IMN & ZIK), Ilmenau University of Technology, 98693 Ilmenau, Germany;4. Department of Chemistry, University College London, London, WC1H 0AJ UK;5. Electronic Measurements Research Laboratory, Ilmenau University of Technology, 98693 Ilmenau, Germany |
| Abstract: | Sodium-ion battery (SIB) is significant for grid-scale energy storage. However, a large radius of Na ions raises the difficulties of ion intercalation, hindering the electrochemical performance during fast charge/discharge. Conventional strategies to promote rate performance focus on the optimization of ion diffusion. Improving interface capacitive-like storage by tuning the electrical conductivity of electrodes is also expected to combine the features of the high energy density of batteries and the high power density of capacitors. Inspired by this concept, an oxide-metal sandwich 3D-ordered macroporous architecture (3DOM) stands out as a superior anode candidate for high-rate SIBs. Taking Ni-TiO2 sandwich 3DOM as a proof-of-concept, anatase TiO2 delivers a reversible capacity of 233.3 mAh g?1 in half-cells and 210.1 mAh g?1 in full-cells after 100 cycles at 50 mA g?1. At the high charge/discharge rate of 5000 mA g?1, 104.4 mAh g?1 in half-cells and 68 mAh g?1 in full-cells can also be obtained with satisfying stability. In-depth analysis of electrochemical kinetics evidence that the dominated interface capacitive-like storage enables ultrafast uptaking and releasing of Na-ions. This understanding between electrical conductivity and rate performance of SIBs is expected to guild future design to realize effective energy storage. |
