AgNbO 3 antiferroelectric (AFE) ceramics have attracted much attention because of their high-energy storage performance and environment-friendly characteristics. In this paper, Sb 2 O 5 -doped AgNbO 3 ceramics are prepared by the traditional solid-state reaction method, and the effects of phase structure, microstructure, dielectric, and ferroelectric properties are systematically investigated. Lattice shrinkage and obvious grain size change are caused by the introduction of Sb 5+ ions. The dielectric constant increases significantly with the introduction of Sb 5+ ( ε r from 210 to 550 at room temperature), and the phase transition temperatures of M 1 –M 2 and M 2 –M 3 shift to a lower temperature as the Sb-doping level increases. High relaxor degree γ = 1.97 of M 1 –M 2 peak is achieved in the AgNb 0.98 Sb 0.02 O 3 ceramics, showing typical relaxor antiferroelectric characteristics. Simultaneously, the relaxor characteristics lead to lower remanent polarization values, a finer P–E hysteresis loop, and an improved AFE phase in AgNb 0.98 Sb 0.02 O 3 ceramics. Compared to pure AgNbO 3 , AgNb 0.98 Sb 0.02 O 3 ceramics have a higher recoverable energy density ( J rec = 1.70 J/cm 3 ) and higher energy efficiency ( η = 30.05%).
Lianshan Ni,Hongyi Chen,Jinqiang Gao,Yu Mei,Haoji Wang,Wentao Deng,Guoqiang Zou,Hongshuai Hou,Xiaobo Ji
Further popularization of ultrahigh-Ni layered cathodes for high-energy lithium-ion batteries (LIBs) is hampered by their grievous structural and interfacial degeneration upon cycling. Herein, by leveraging the strong electronegativity and low solubility properties of Sb element, a multifunctional modification that couples atomic/microstructural reconstruction with interfacial shielding is well designed to improve the LiNi0.94Co0.04Al0.02O2 (NCA) cathode by combining Sb5+ doping and Li7SbO6 coating. Notably, a robust O framework is established by regulating local O coordination owing to the incorporation of a strong Sb–O covalence bond, leading to the inhibited lattice O evolution at high voltage, as revealed by synchrotron X-ray absorption spectroscopy. Moreover, the radially aligned primary particles with (003) crystallographic texture and refined/elongated sizes are achieved by the pinning of Sb on grain boundaries and are confirmed by scanning transmission electron microscopy, resulting in the fast Li+ diffusion and mitigated particle cracking. Additionally, in situ construction of the Li7SbO6 ionic conductive layer on grain boundaries can effectively boost interfacial stability and Li+ kinetics. As a result, the optimal Sb-modified NCA delivers a high capacity retention of 94.6% after 200 cycles at 1 C and a good rate capacity of 183.9 mAh g–1 at 10 C, which is expected to be applied to next-generation advanced LIBs.
危险品化学品经营许可证（带存储）