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Mn/V Co-Doping Enables Multielectron Transfer and Above-Theoretical Capacity in Na4Fe3(PO4)2P2O7 Cathode
Ying Tang1, Xinyu Guo1, Junyang Wang2
1School of Advanced Materials, Peking University Shenzhen Graduate School, Shenzhen, China.
Small Methods
|June 24, 2026
Summary
This study developed a novel composite cathode for sodium-ion batteries, exceeding theoretical capacity limits. The advanced material demonstrates high energy density and excellent stability for practical applications.
Area of Science:
- Materials Science
- Electrochemistry
- Energy Storage
Background:
- Polyanionic cathodes in sodium-ion batteries face limitations in theoretical capacity and kinetics.
- Existing materials struggle to meet the demands for high-energy-density applications.
Purpose of the Study:
- To overcome the limitations of polyanionic cathodes in sodium-ion batteries.
- To develop a high-performance cathode material with enhanced capacity and kinetics.
- To achieve breakthroughs in energy density and cycling stability.
Main Methods:
- Synergistic strategy involving Mn/V co-doping.
- Dual-carbon modification: in situ carbon coating and carbon nanotube networking.
- Synthesis of Na3.5Fe2Mn0.5V0.5(PO4)2P2O7/C@CNT (NFMVPP) composite cathode.
Main Results:
- NFMVPP cathode achieved an initial discharge capacity of 149.11 mAh g-1, surpassing the theoretical limit.
- Remarkable energy density of 398.44 Wh kg-1 achieved at 0.05 C.
- Excellent rate capability (86.02 mAh g-1 at 20 C) and robust long-term cycling stability demonstrated.
Conclusions:
- The developed NFMVPP cathode material offers a new paradigm for high-energy-density sodium-ion batteries.
- Mn/V co-doping and dual-carbon modification are effective strategies to enhance polyanionic cathode performance.
- This research paves the way for practical deployment of advanced sodium-ion battery technologies.
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