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Substituting inert phosphate with redox-active silicate towards advanced polyanion-type cathode materials for sodium-ion batteries.
- Source :
-
Nanoscale [Nanoscale] 2023 Feb 16; Vol. 15 (7), pp. 3345-3350. Date of Electronic Publication: 2023 Feb 16. - Publication Year :
- 2023
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Abstract
- Polyanion-type phosphate materials with Na-super-ionic conductor structures are promising for next-generation sodium-ion battery cathodes, although the intrinsically low electroconductivity and limited energy density have restricted their practical applications. In this study, we put forward substituting an inert phosphate with a redox-active silicate to improve the energy density and intrinsic electroconductivity of polyanion-type phosphate materials, thus enabling an advance in sodium-ion battery cathodes. As a proof of concept, some of the phosphate of Na <subscript>3</subscript> V <subscript>2</subscript> (PO <subscript>4</subscript> ) <subscript>3</subscript> was replaced by silicate to fabricate Na <subscript>3</subscript> V <subscript>2</subscript> (PO <subscript>4</subscript> ) <subscript>2.9</subscript> (SiO <subscript>4</subscript> ) <subscript>0.1</subscript> , which exhibited a higher average discharge voltage of 3.36 V and a higher capacity of 115.8 mA h g <superscript>-1</superscript> than pristine Na <subscript>3</subscript> V <subscript>2</subscript> (PO <subscript>4</subscript> ) <subscript>3</subscript> (3.31 V, 109.6 mA h g <superscript>-1</superscript> ) at 0.5 C, therefore improving the energy density. Moreover, the introduced silicate enhanced the intrinsic electroconductivity of Na <subscript>3</subscript> V <subscript>2</subscript> (PO <subscript>4</subscript> ) <subscript>3</subscript> materials, as confirmed by both theoretical simulation and electrochemical measurements. After pairing with a commercial hard carbon anode, the optimized Na <subscript>3</subscript> V <subscript>2</subscript> (PO <subscript>4</subscript> ) <subscript>2.9</subscript> (SiO <subscript>4</subscript> ) <subscript>0.1</subscript> cathode enabled a stable-cycling full cell with 90.1% capacity retention after 300 cycles at 5 C and a remarkable average coulombic efficiency of 99.88%.
Details
- Language :
- English
- ISSN :
- 2040-3372
- Volume :
- 15
- Issue :
- 7
- Database :
- MEDLINE
- Journal :
- Nanoscale
- Publication Type :
- Academic Journal
- Accession number :
- 36722741
- Full Text :
- https://doi.org/10.1039/d2nr06602e