电介质储能材料因为具有高功率密度和快速充放电特性，在脉冲/大功率领域有着巨大的需求。其中，铌酸银(AgNbO₃)基反铁电陶瓷因其双电滞回线特征导致了优异的储能性能，受到越来越多的关注。然而，亚铁电性的存在及反铁电-铁电相变导致的回滞效应会产生较大的损耗，限制了其储能性能的提升。因此，本文在采用水热法制备铌酸银陶瓷的基础上，通过离子掺杂改性和核壳结构构筑优化铌酸银基陶瓷储能性能。系统研究了陶瓷物相结构、微观结构、能带结构以及介电、绝缘特性对储能性能的影响规律，为开发具有高储能密度和效率的AgNbO₃基反铁电陶瓷提供技术参考。

首先，选用大离子半径、低离子极化率的Hf⁴⁺对铌酸银B位进行掺杂。研究发现，随着Hf⁴⁺掺杂量增加，AgNb_1-0.8xHf_xO₃(ANH-x，x = 0~0.04)陶瓷的AFE相稳定性略微增强。紫外测试结合电子能带计算结果发现，Hf⁴⁺取代的AgNbO₃带隙宽度增加。证明Hf⁴⁺掺杂有利于改善陶瓷能带结构，进而增加ANH-x陶瓷的击穿场强(E_b)。因此在引入0.02 mol的Hf⁴⁺掺杂B位后，陶瓷在240 kV/cm的外加电场下取得了2.27 J/cm³的储能密度(W_rec)，是纯AN陶瓷的1.23倍。

优选AgNb_0.984Hf_0.02O₃组分，引入小离子半径的La³⁺对其A位进行掺杂，制备A/B位共掺杂的Ag_1-3xLa_xNb_0.984Hf_0.02O₃(ALNH-x，x = 0~0.04)陶瓷。研究发现，La³⁺能将ANH-0.02陶瓷的M₁-M₂相变温度移至室温以下，并使M₂-M₃和M₃-O₁相变温度不断降低，有效增强AFE相稳定性。同时，La³⁺/Hf⁴⁺共掺可以诱导弛豫行为，细化电滞回线，有利于提高η。随着La³⁺掺杂量增加，陶瓷晶粒尺寸减小，击穿场强增加，反铁电性极大增强，且电滞回线逐渐细化。当La³⁺的掺杂量为0.02 mol时，W_rec达到最大值2.73 J/cm³，η为54%。

选取储能性能最佳的La³⁺/Hf⁴⁺共掺杂组分，通过核壳结构设计获得具有更高W_rec和η的AgNbO₃基反铁电陶瓷。在ALNH陶瓷粉体表面包覆高绝缘的SiO₂和ZnO壳层，研究不同包覆层厚度的陶瓷粉体烧结后对ALNH陶瓷结构和性能的影响。研究结果表明，ZnO包覆的ALNH陶瓷具有更加致密的微观形貌、更小的晶粒尺寸和更大的介电常数。随着ZnO包覆量的增加，击穿场强从280 kV/cm增加至340 kV/cm。当包覆量为3 wt.%时，陶瓷获得了3.36 J/cm³的W_rec和64%的η。本研究表明，合理的组分设计以及核壳结构构筑是提升AN基陶瓷储能性的有效手段，为储能陶瓷的研究提供了新的思路。

Dielectric energy storage materials that exhibit high power density and rapid charging/discharging capabilities are in high demand for pulse and high-power applications. Among these, lead-free silver niobate (AgNbO₃) antiferroelectric ceramics have garnered increasing attention due to their unique double hysteresis return line characteristics, which contribute to exceptional energy storage performance. However, the presence of subferroelectricity and the hysteresis effect due to the antiferroelectric-ferroelectric phase transition produces large losses, limiting the improvement of its energy storage performance. Therefore, in this paper, based on the preparation of silver niobate ceramics by the hydrothermal method, the energy storage performance of silver niobate-based ceramics is optimized through ion doping modification and core-shell structure construction. The effects of phase structure, microstructure, energy band structure, dielectric, and insulating properties on energy storage performance are systematically investigated to provide technical references for the development of AgNbO₃-based antiferroelectric ceramics with high energy storage density and efficiency.

Firstly, Hf⁴⁺, which has a large ionic radius and low ionic polarizability, was selected to dope the B-site of silver niobate. It was found that the AFE phase stability of AgNb_1-0.8xHf_xO₃ (ANH-x, x = 0~0.04) ceramics was slightly enhanced with the increase of Hf⁴⁺ doping. UV tests combined with electronic energy band calculations revealed an increase in the band gap width of Hf⁴⁺-substituted AgNbO₃. It is demonstrated that Hf⁴⁺ doping favors the improvement of the ceramic energy band structure, which in turn increases the breakdown field strength (E_b) of ANH-x ceramics. After introducing 0.02 mol of Hf⁴⁺ doped B-site, the ceramics achieved an energy storage density (W_rec) of 2.27 J/cm³, which is 1.23 times higher than that of pure AN ceramics, under an applied electric field of 240 kV/cm.

The AgNb_0.984Hf_0.02O₃ component was preferentially selected, and La³⁺ ions with a small ionic radius were introduced for A-site doping, resulting in the preparation of A/B co-doped Ag_1-3xLa_xNb_0.984Hf_0.02O₃ (ALNH-x, x = 0~0.04) ceramics. It was found that La³⁺ could shift the M₁-M₂ phase transition temperature of ANH-0.02 ceramics below room temperature while leading to a decrease in the M₂-M₃ and M₃-O₁ phase transition temperatures, effectively enhancing the antiferroelectric phase. Simultaneously, La³⁺/Hf⁴⁺ co-doping can induce relaxation behavior and refine the hysteresis loop, which contributes to the improvement of η. As the concentration of La³⁺ doping increases, the ceramic grain size decreases, the breakdown field strength increases, antiferroelectricity is significantly enhanced, and the hysteresis loop is gradually refined. When the doping amount of La³⁺ is 0.02, W_rec attains a maximum value of 2.73 J/cm³ and η is 54%.

The La³⁺/Hf⁴⁺ co-doped component with the best energy storage performance is selected to obtain AgNbO₃-based antiferroelectric ceramics with higher W_rec and η through core-shell structure design. Highly insulating SiO₂ and ZnO shell layers were coated on the ALNH surface to investigate the effects of varying coating thicknesses on the structure and properties of ALNH ceramics. The results show that the ZnO-coated ALNH ceramics exhibit denser microstructures, smaller grain sizes, and larger dielectric constants. The breakdown field strength increased from 280 kV/cm to 340 kV/cm with the increase in ZnO coating amount. ALNH@3wt.%ZnO ceramics achieved a W_rec of 3.36 J/cm³ and η of 64%. This study demonstrates that the rational component design and the construction of core-shell structures are effective means to enhance the energy storage properties of AN-based ceramics, which provide a new perspective for the study of energy storage ceramics.