Energy Storage Materials
·
2025
·
IF 20.2
Yong Li,Qiming Xiao,Yun Zhao,Shu Zhao,Bin Liu
Alluaudite-type Na 2+2x Fe 2-2x (SO 4 ) 3 (NFS) compounds, as a promising polyanionic cathode material for sodium-ion batteries (SIBs), have attracted considerable attention owing to their cost-effectiveness and elevated operating voltage. Nevertheless, practical implementation of NFS has been hindered by inherent limitations including insufficient crystallinity and compromised electronic/ionic conductivity. Herein, we propose a pioneering dual-strategy integrating cation substitution with crystal engineering to synthesize Mg 2+ -doped single-crystalline NFS enveloped by flash graphene (denoted as [email protected] ). Through synchrotron radiation characterization complemented by density functional theory (DFT) simulations, we verified the preferential occupation of magnesium at the target iron site. Notably, while preserving the fundamental alluaudite framework, this strategic doping induced a band structure modulation with reduced bandgap and diminished Na⁺ diffusion barriers, synergistically enhancing charge transfer kinetics. The optimized [email protected] cathode delivers remarkable rate performance (63 mAh g -1 at 100C vs 21 mAh g -1 for the undoped counterpart) and unprecedented cyclability, retaining 92.8 % capacity after 7,000 cycles at 50C. In addition, the pillar effect of Mg 2+ in the crystal, as evidenced by in-situ XRD results, greatly inhibited the migration of Fe 3+ during cycling, maintaining the stable structure and resulting in outstanding cycling stability under drastic conditions. These findings establish a universal crystal engineering paradigm for developing high-performance polyanionic cathodes in energy storage systems.
研究领域:
材料科学
·
电化学
·
储能技术
·
纳米技术
·
固态化学
✓ 已验证
产品关联
DOI
高影响因子
ACS Nano
·
2026
·
IF 16
Jingjing Hou,Shizhong Lv,Jian Liu,Jiaji Tang,Yuwei Wang,Lirui Liu,Zaohui He,Gang Sun,Ai-Min Lv,Liang Deng,Yunlong Zhang,Lei Zhao,Zhenbo Wang
Sodium-ion batteries hold promise for grid-scale energy storage thanks to abundant resources and superior safety, but their wide-temperature operation is hindered by sluggish electronic–ionic transport and structural instability of cathode materials. Herein, a cation-intermixing strategy driven by stoichiometric regulation is proposed for Na2+2xFe2–x(SO4)3 cathodes, which can simultaneously enhance structural stability, improve charge transfer, and facilitate Na+ transport kinetics. Specifically, derived Fe vacancies and concomitant Na+ insertion reconstruct the electronic environment, strengthening Fe–O bonds to stabilize the crystal framework while optimizing Fe 3d electron energy level distribution to facilitate charge transfer. This alteration concurrently widens Na+ migration channels and reduces diffusion barriers, enabling rapid ion transport. Consequently, the Na2.48Fe1.76(SO4)3 cathode (x = 0.24 in Na2+2xFe2–x(SO4)3, with a Na/Fe molar ratio of 1.4) with optimal cation intermixing exhibits exceptional wide-temperature performance. It delivers 85.9% capacity retention following 3000 cycles at 30 C (25 °C) and 88.3% following 4000 cycles at 1 C (−20 °C). Even at an ultrahigh 100 C (60 °C), it still retains 83.2% relative to its capacity measured at 25 °C and 0.1 C. This work provides a stoichiometry-driven approach to designing superior-performance sulfate-based cathodes for wide-temperature sodium-ion batteries.
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Energy Storage Materials
·
2026
·
IF 19.3
Xizhao Wang,Xingshuang Wu,Fenghua Zheng,Lang Zhao,Hongbo Chen,Min Tang,Xinyou He,Wei Xu,Xiangdong Zhu,Zhiming Xiao,Xinghui Liang,Lei Ming,Xing Ou
Alluaudite-type Na 2+2x Fe 2−x (SO 4 ) 3 is considered as a promising cathode for large-scale energy storage due to its high structural stability and cost-effectiveness. However, due to low theoretical specific capacity, NFS still exhibits insufficient overall cost competitiveness, and it also suffers from low intrinsic electrical conductivity. Here, we propose a direct regeneration strategy based on industrial byproducts to prepare a low-cost and high-conductivity Na 2.56 Fe 1.65 Mg 0.05 Mn 0.014 Al 0.006 (SO 4 ) 3 cathode. Compared to traditional synthetic routes for pure compounds, the direct degeneration of industrial byproducts can reduce iron source costs by approximately 83%. In addition, Mg, Mn and Al impurities from industrial byproducts are in situ doped into the polyionic framework, achieving functionalized utilization. Mg/Mn/Al co-doping not only induces strong interactions with oxygen to stabilize the crystal structure, but also decreases Na + migration energy barriers and enhances the electrical conductivity. Na 2.56 Fe 1.65 Mg 0.05 Mn 0.014 Al 0.006 (SO 4 ) 3 exhibits low lattice strain and uniform ion concentration distribution during electrochemical processes, demonstrating excellent rate capability and cycling stability. It shows 100% capacity retention after 1500 cycles at 3 C, and delivers a high discharge capacity of 50.16 mAh g −1 at 30 C. This study provides a scalable route for the valorization of industrial waste and the development of low-cost, high-performance polyanionic cathodes for sodium-ion batteries.
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DOI
高影响因子
Nanoscale
·
2025
·Vol. 17
·期 35
·20465-20475
·
IF 5.1
Weiyi Li,Min Zhang,Shen Cai,Yan Xin,Huajun Tian
Alluaudite-type Na2+2xFe2−x(SO4)3 has been a promising cathode material for sodium-ion batteries (SIBs) due to its high operating voltage and stable structure. However, its actual electrochemical performance suffers from intrinsic sluggish kinetics and poor electronic conductivity. In this work, for the first time, we propose a Na2.48(Fe0.89Mg0.03Sn0.04)1.76(SO4)3 cathode material prepared via a Mg/Sn co-doping strategy. Inactive Mg2+ stabilizes the structure, while Sn4+ inhibits the decomposition of electrolytes under high voltage. The Mg/Sn co-doping strategy enhances the kinetics of sodium ion diffusion reactions, leading to improved electrochemical properties, especially at low temperatures. The optimal NFMS/C-Sn0.03 cathode exhibits a long-term capacity retention of 91.6% after 1500 cycles at 5C and outstanding reversible capacities of 74.3 and 58.3 mAh g−1 at 10C and even at 50C, respectively. Furthermore, the NFMS/C-Sn0.03 cathode demonstrates a high capacity retention of 95.5% at −5 °C and 88.4% at −15 °C, with a remarkable capacity retention of 93.9% after 1000 cycles at room temperature and 85.5% after 700 cycles at −15 °C, respectively. Electron paramagnetic resonance (EPR) and atomic force microscopy (AFM) techniques confirmed that the presence of unpaired electrons and enhanced electronic conductivity could be attributed to the Mg/Sn co-doping. This work provides a feasible approach for designing low-cost, durable, low-temperature, and high-performance cathode materials for SIBs.
研究领域:
材料科学
·
电化学
·
储能
·
电池技术
✓ 已验证
产品关联
DOI
PubMed
高影响因子
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