Yazar "Gao, Jinqiang" seçeneğine göre listele

Listeleniyor 1 - 2 / 2
  • Küçük Resim Yok
    Öğe
    Manipulating Local Chemistry and Coherent Structures for High-Rate and Long-Life Sodium-Ion Battery Cathodes
    (Amer Chemical Soc, 2024) Wang, Haoji; Chen, Hongyi; Mei, Yu; Gao, Jinqiang; Ni, Lianshan; Hong, Ningyun; Zhang, Baichao
    Layered sodium transition-metal (TM) oxides generally suffer from severe capacity decay and poor rate performance during cycling, especially at a high state of charge (SoC). Herein, an insight into failure mechanisms within high-voltage layered cathodes is unveiled, while a two-in-one tactic of charge localization and coherent structures is devised to improve structural integrity and Na+ transport kinetics, elucidated by density functional theory calculations. Elevated Jahn-Teller [Mn3+O6] concentration on the particle surface during sodiation, coupled with intense interlayer repulsion and adverse oxygen instability, leads to irreversible damage to the near-surface structure, as demonstrated by X-ray absorption spectroscopy and in situ characterization techniques. It is further validated that the structural skeleton is substantially strengthened through the electronic structure modulation surrounding oxygen. Furthermore, optimized Na+ diffusion is effectively attainable via regulating intergrown structures, successfully achieved by the Zn2+ inducer. Greatly, good redox reversibility with an initial Coulombic efficiency of 92.6%, impressive rate capability (86.5 mAh g(-1) with 70.4% retention at 10C), and enhanced cycling stability (71.6% retention after 300 cycles at 5C) are exhibited in the P2/O3 biphasic cathode. It is believed that a profound comprehension of layered oxides will herald fresh perspectives to develop high-voltage cathode materials for sodium-ion batteries.
  • Küçük Resim Yok
    Öğe
    Multivalent Cation Incorporated into Manganese-Iron Based NASICON Cathodes for High Voltage Sodium-Ion Batteries
    (Wiley-V C H Verlag Gmbh, 2024) Zeng, Jingyao; Gao, Jinqiang; Jian, Weishun; Wang, Haoji; Li, Wenyuan; Hong, Ningyun; Zhang, Baichao
    Na4Mn1.5Fe1.5(PO4)(2)P2O7 (NMFPP), with its low cost and high energy density, is essential for accelerating the commercialization of sodium-ion batteries. However, its practical application is limited by serious voltage hysteresis and detrimental Jahn-Teller distortions. Herein, a high operating voltage and superior stable Nb-doped NMFPP with fewer intrinsic anti-site defects are elaborately designed by the reconstruction of the crystal lattice and electronic distribution. By introducing higher charge density Nb & horbar;O bonds, the lengths of Mn-O bonds are shortened, enhancing lattice stability. As a result, the lattice volume contracted during Na+ extraction/insertion is decreased with niobium-modified Na-4(Mn0.5Fe0.5)(2.94)Nb-0.06(PO4)(2)P2O7, mitigating lattice distortion from the Jahn-Teller effect and increasing the capacity retention after 1000 cycles from 57.5% to 82.3%. More importantly, the delayed effect of Mn2+ involvement in redox reactions is significantly reduced, raising the average operating voltage from 3.32 to 3.64 V and increasing the overall energy density by 13%. This study opens new avenues to develop advanced sodium-ion battery cathode materials with high energy density and long calendar life for energy storage.