Structurally stable electrodeposited vanadium pentoxide inverse opal networks on FTO-coated glass are electrochemically tested as a function of C-Rate (discharging and charging) in this study. Recent applications of IOs in electrochemical energy storage have proven that their open-worked structure promotes more stable Li-ion intercalation during cycling(1-3), exhibit improved rate capability due to increased surface area and decreased path lengths for Li⁺ insertion,(4-7). Rate limitations associated with standard Li-ion batteries can be improved in principle due to shorter diffusion lengths in the 3D architecture(8, 9), particularly important for charging in full cells. V₂O₅ has been widely investigated(10) as a cathode material for Li-ion batteries due to its high theoretical specific capacity and is useful for reversible Li-ion insertion and removal due to its mixed valance and layered structure.(11) The difference in open-topped versus overfilled (closed top) 3D inverse opal macroporous V₂O₅ networks, due to electrodeposition growth time, is examined by galvanostatic cycling, and both 3D structure are examined at C-rates in the range 0.5 – 30 C. Electrochemical analysis demonstrates how lithium phase changes increasing C-rate in both open and overfilled network cases, with capacity values investigated after 25 charge/discharge cycles. Raman scattering and X-ray diffraction is used to investigate the change in structure and phase in each case at each C-rate, along with SEM images to visual investigate the effect of C-rate on the V₂O₅ inverse opal networks.

References

1. E. Armstrong and C. O'Dwyer, J. Mater. Chem. C, 3, 6109 (2015).

2. Y. Zhao, X. Li, J. Liu, C. Wang, Y. Zhao and G. Yue, ACS Appl. Mater. Interfaces (2016).

3. E. Armstrong, D. McNulty, H. Geaney and C. O’Dwyer, ACS Appl. Mater. Interfaces (2015).

4. M. Osiak, H. Geaney, E. Armstrong and C. O'Dwyer, J. Mater. Chem. A, 2, 9433 (2014).

5. F. Zhang, Y. Tang, H. Liu, H. Ji, C. Jiang, J. Zhang, X. Zhang and C.-S. Lee, ACS Appl. Mater. Interfaces (2016).

6. Y. Liang, L. Chen, L. Cai, H. Liu, R. Fu, M. Zhang and D. Wu, Chem. Commun (2016).

7. F. Li, M. Zeng, J. Li, X. Tong and H. Xu, RSC Adv. (2016).

8. D. R. Rolison, J. W. Long, J. C. Lytle, A. E. Fischer, C. P. Rhodes, T. M. McEvoy, M. E. Bourg and A. M. Lubers, Chem. Soc. Rev, 38, 226 (2009).

9. C. O'Dwyer, Adv. Mater. 28, 5681 (2016).

10. D. McNulty, D. N. Buckley and C. O'Dwyer, J. Power Sources, 267, 831 (2014).

11. E. Armstrong, M. O'Sullivan, J. O'Connell, J. D. Holmes and C. O'Dwyer, J. Electrochem. Soc, 162, D605 (2015).