October 28, 2021
Inorganic Cathode Materials for Rechargeable Batteries from Lithium to Sodium Storage
Lithium-ion battery (LIB) as a powerful energy storage system is used to power many things from mobile phones to electric vehicles. The harvested green but intermittent solar and wind energy can also be stored in LIBs. While LIBs dominate the market, scarcity of Li resources has brought our community to concerns about the sustainable development of LIBs in the long run. Sodium-ion batteries (SIBs) as immediate and low-cost alternatives to LIBs have caught much researchers’ attention. However, accommodation of large Na ions in host electrode materials could be difficult and thus development of high performance electrode materials especially cathode materials is essential for advancement of SIBs as a more practical energy storage system.
In this thesis, vanadium oxides were selected to systematically study the impacts of phase structures, carbon matrices and morphologies on electrochemical properties of cathode materials for Li and Na storage. Then, cathode materials in Fe-PO4-F chemical space have been originally explored based on the concepts of stable polyanion framework, off-stoichiometry and metastability, aiming at development of advanced and sustainable cathode materials for SIBs. All the studied materials show electrochemical activity.
Particularly, metastable Na1.2Fe1.2PO4F0.6 material displays the best performance with energy density of nearly 400 Wh kg-1 attained at the material level, with good reversibility and stability. Besides, activated iron-rich Na0.6Fe1.2PO4 material was first found to show excellent long term cycling performance and rate capability and more than 350 Wh kg-1 energy density can be attained at the material level.
Overall, Li storage and Na storage were compared in the case of VOx@rGO cathode materials and, moreover, a promising new class of iron-based polyanionic cathode materials were explored for SIBs. This work could as guidelines for future investigation and development of new cathode materials.
Jury members :
- Prof. Alexandru Vlad (UCLouvain), supervisor
- Prof. Yann Garcia (UCLouvain), chairperson
- Prof. Sophie Hermans (UCLouvain), secretary
- Prof. Jean-François Gohy (UCLouvain)
- Prof. Jun Chen (Nankai University, China)
- Prof. Jilei Liu (Hunan University, China)
- Prof. Bao-Lian Su (Université de Namur)
Pay attention :
The public defense of Xuelian Liu scheduled for Thurdsay 28 October at 1:00 p.m will take place in the form of a video conference