Publications by authors named "Yi-Hu Feng"

Article Synopsis
  • Sodium-ion batteries (SIBs) are gaining popularity for large-scale energy storage due to the affordability and availability of sodium resources, but achieving high energy density and stable performance remains difficult.
  • A new hierarchical structure in the cathode material NaLiMgNiFeMnTiO features a protective P2 crystalline shell around a bulk O3 phase, which helps prevent damage during battery charge and discharge cycles.
  • This innovative design results in impressive electrochemical performance, with an energy density of 506 Wh/kg and a retention rate of 85.5% over 200 cycles, emphasizing the significance of optimizing crystalline structures for enhanced battery durability.
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Article Synopsis
  • High-voltage sodium metal batteries (SMBs) are promising for high-energy-density applications due to the cost and abundance of sodium, but they face challenges like capacity decay from electrolyte decomposition and safety issues from reactive components.
  • A new dual-anion aggregated sodium solvation structure in a nonflammable electrolyte is proposed, forming a stable cathode/electrolyte interphase that reduces unwanted reactions and enhances stability and sodium transport.
  • The NaNiFeMnTiO//Na batteries using this electrolyte achieved a discharge capacity of 167.5 mAh/g with 85.2% capacity retention over 800 cycles, showcasing a potential strategy for safer, high-voltage SMBs.
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Article Synopsis
  • Researchers are exploring sodium-ion batteries for high energy-density electrodes, identifying Na-deficient intercalation compounds with lattice oxygen redox as potential high-capacity cathodes.
  • The study tackled issues with poor electrochemical reversibility in redox reactions by using lithium orbital hybridization to engineer a new cathode material, P2-NaLMCM', enhancing oxygen redox stability.
  • Results showed that P2-NaLMCM' achieved a high capacity of 183.8 mAh/g and maintained 80.2% capacity retention over 200 cycles, offering promising advancements in battery technology.
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In spite of the competitive performance at room temperature, the development of sodium-ion batteries (SIBs) is still hindered by sluggish electrochemical reaction kinetics and unstable electrode/electrolyte interphase under subzero environments. Herein, a low-concentration electrolyte, consisting of 0.5M NaPF dissolving in diethylene glycol dimethyl ether solvent, is proposed for SIBs working at low temperature.

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O3-type layered oxides with high initial sodium content are promising cathode candidates for Na-ion batteries. However, affected by the undesired transition metal slab sliding and reaction with HO/CO, their further application is typically hindered by unsatisfactory cycling stability upon charging to high voltage and poor storage stability under humid air. Herein, we demonstrate a Fe/Ti cosubstitution strategy to simultaneously enhance the electrochemical performance and storage stability of pristine O3-NaNiMnO cathode material, via employing high redox potential and inactive stabilized dopants.

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Lithium-ion batteries (LIBs) are at the forefront of energy storage and highly demanded in consumer electronics due to their high energy density, long battery life, and great flexibility. However, LIBs usually suffer from obvious capacity reduction, security problems, and a sharp decline in cycle life under low temperatures, especially below 0 °C, which can be mainly ascribed to the decrease in Li diffusion coefficient in both electrodes and electrolyte, poor transfer kinetics on the interphase, high Li desolvation barrier in the electrolyte, and severe Li plating and dendrite. Targeting such issues, approaches to improve the kinetics and stability of cathodes are also dissected, followed by the evaluation of the application prospects and modifications between various anodes and the strategies of electrolyte design including cosolvent, blended Li salts, high-concentration electrolyte, and additive introduction.

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O3-NaNiFeMnO layered oxide is considered one of the most promising cathode candidates for sodium-ion batteries because of its advantages, such as its large capacity and low cost. However, the practical application of this material is limited by its poor cyclic stability and insufficient rate capability. Here, a strategy to substitute the Fe in NaNiFeMnO with Al is adopted to address these issues.

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Layered oxide cathodes usually exhibit high compositional diversity, thus providing controllable electrochemical performance for Na-ion batteries. These abundant components lead to complicated structural chemistry, closely affecting the stacking preference, phase transition and Na kinetics. With this perspective, we explore the thermodynamically stable phase diagram of various P2/O3 composites based on a rational biphasic tailoring strategy.

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