Given the remarkable performances of Ruddlesden-Popper (RP) type oxides in electronic devices, the study of their intrinsic dielectric, magnetic and electromagnetic microwave (EMW) absorption properties are still missing. Herein, two kinds of Lead-free relaxor-ferroelectric BNT-based ceramic hierarchical polycrystalline alloys (La₃Ni₂O₇/LaNiO₃, La₂NiO₄/La₂O₃) were prepared via a facile solvothermal and high-temperature annealing technique as high-performance EMW absorption materials (MAMs). By a means of adjustment of solvothermal time in the precursor systems, Nickel salt layers precipitation declined gradually. The phase and crystal state of the powders were characterized by X-ray diffraction (XRD) with refinement treatment (Rietveld analysis). XPS was utilized on the determination of interstitial O^2– quantitatively in La₃Ni₂O_7+δ (δ = 1.95) and La₂NiO_4+δ (δ = 0.75). Responsible to the synergistic effect of dielectric and magnetic response and well-matched impedance, the as-fabricated MAMs performed excellent wave absorbability, especially in low frequency (S-band). In details, La₃Ni₂O₇/LaNiO₃ achieved optimal effective absorption band (f_E) 3.36 GHz at 9.52–12.80 GHz and a minimum reflection loss (RL_min) −43.30 dB with a thickness of 2.2 mm. Moreover, La₃Ni₂O₇/LaNiO₃ and La₂NiO₄/La₂O₃ overcame the challenge of absorbers’ thickness in S-band, of which the RL reached –22.63 and −29.90 dB at 0.7 mm, respectively. Noteworthily, La₃Ni₂O₇/LaNiO₃ obtained RL value of −50.06 dB at 10.72 GHz with a device thickness of 2.8 mm. It is emphasized that this report has interpreted the EMW absorption capacity and mechanism exhaustively, which will initiate simultaneous enhancement of recoverable energy density and efficiency application of RPs.

鉴于Ruddlesden-Popper（RP）型氧化物在电子设备中的卓越性能，对其内在电介质，磁和电磁微波（EMW）吸收特性的研究仍处于缺失状态。本文中，两种无铅弛豫铁电BNT基陶瓷分层多晶合金（La ₃ Ni ₂ O ₇ / LaNiO ₃，La ₂ NiO ₄ / La ₂ O ₃）是通过一种容易的溶剂热和高温退火技术制备的，作为高性能的EMW吸收材料（MAM）。通过调整前体系统中的溶剂热时间，镍盐层的沉淀逐渐减少。通过细化处理（Rietveld分析）的X射线衍射（XRD）表征粉末的相和晶体状态。XPS用于定量测定La ₃ Ni ₂ O _{7 +δ}（δ  = 1.95）和La ₂ NiO _{4 +δ}（δ）中的间隙O ^2– = 0.75）。由于介电和磁响应的协同效应以及阻抗的匹配，所制造的MAM具有出色的波吸收性，尤其是在低频（S波段）中。详细地讲，La ₃ Ni ₂ O ₇ / LaNiO ₃在9.52–12.80 GHz时达到了最佳有效吸收带（f _E）3.36 GHz，厚度为2.2 mm，最小反射损耗（RL _min）−43.30 dB。此外，La ₃ Ni ₂ O ₇ / LaNiO ₃和La ₂ NiO ₄ / La ₂ O ₃克服了S波段吸收器厚度的挑战，在0.7毫米处，RL分别达到–22.63和-29.90 dB。值得注意的是，La ₃ Ni ₂ O ₇ / LaNiO ₃在装置厚度为2.8 mm时，在10.72 GHz时的RL值为-50.06 dB。需要强调的是，本报告已经详尽地解释了EMW的吸收能力和机理，这将启动同时提高可回收能量密度和RPs的效率应用。