Repeated cold rolling and folding is employed to fabricate a metallurgical composite of sodium–antimony–telluride Na2(Sb2/6Te3/6Vac1/6) dispersed in electrochemically active sodium metal, termed “NST‐Na.” This new intermetallic has a vacancy‐rich thermodynamically stable face‐centered‐cubic structure and enables state‐of‐the‐art electrochemical performance in widely employed carbonate and ether electrolytes. NST‐Na achieves 100% depth‐of‐discharge (DOD) in 1
Sodium‐metal batteries (SMBs) are considered as a compliment to lithium‐metal batteries for next‐generation high‐energy batteries because of their low cost and the abundance of sodium (Na). Herein, a 3D nanostructured porous carbon particle containing carbon‐shell‐coated Fe nanoparticles (PC‐CFe) is employed as a highly reversible Na‐metal host. PC‐CFe has a unique 3D hierarchy based on sub‐micrometer‐sized carbon particles, ordered open channels, and evenly distributed carbon‐coated Fe nanoparticles (CFe) on the surface. PC‐CFe achieves high reversibility of Na plating/stripping processes over 500 cycles with a Coulombic efficiency of 99.6% at 10 mA cm–2with 10 mAh cm–2in Na//Cu asymmetric cells, as well as over 14 400 cycles at 60 mA cm–2in Na//Na symmetric cells. Density functional theory calculations reveal that the superior cycling performance of PC‐CFe stems from the stronger adsorption of Na on the surface of the CFe, providing initial nucleation sites more favorable to Na deposition. Moreover, the full cell with a PC‐CFe host without Na metal and a high‐loading Na3V2(PO4)3cathode (10 mg cm–2) maintains a high capacity of 103 mAh g–1at 1 mA cm–2even after 100 cycles, demonstrating the operation of anode‐free SMBs.
more » « less- PAR ID:
- 10365564
- Publisher / Repository:
- Wiley Blackwell (John Wiley & Sons)
- Date Published:
- Journal Name:
- Advanced Materials
- Volume:
- 34
- Issue:
- 14
- ISSN:
- 0935-9648
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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