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Owing to the flammability of dendrites and organic liquid electrolytes, the safety performance of lithium-ion batteries cannot be effectively ensured. The sodium-ion solid electrolyte is anticipated to become the leading next generation battery in commercial applications due to the high thermal stability and low price. Yet, the insufficient ionic conductivity of Na3Zr2Si2PO12 solid electrolytes, along with the large interfacial resistance between the cathode material and the solid electrolyte, substantially restricts the performance of room-temperature all-solid-state sodium rechargeable batteries. In the present study, the effects of Bi2O3 additive on the phase, microstructure and ionic conductivity of Na3.1Y0.1Zr1.9Si2PO12 ceramic electrolyte are reported. Moreover, a significant room temperature conductivity of 1.21 × 10-3 S cm-1 and the dense microstructure was attained by adding 1 wt% Bi2O3 to Na3.1Y0.1Zr1.9Si2PO12 sintered at 1100 °C for 6 h. Simultaneously, an electrochemical test exhibited that the electrochemical stability window increased to 4.8 V and revealed good cycle stability.

Inorganic ceramic as one of the most promising candidate for solid state electrolytes (SSEs) have received extensive attention due to their excellent thermal stability, good electrochemical stability and wide electrochemical window. The sodium super ionic conductor (NASICON, Na3Zr2Si2PO12) structure possesses a three-dimensional network, which helps the migration of Na+. However, because of its low Na+ ion conductivity and poor sintering performance, Na3Zr2Si2PO12 is difficult to achieve application. Therefore, it is quite urgent to solve these questions. In this study, we have reported the effects of additive antimony-tin oxide (ATO) on the phase, microstructure and ionic conductivity of Na3Zr2Si2PO12 ceramic electrolytes. With the ATO sintering additive added, the Na+ ion conductivity and density of Na3Zr2Si2PO12 ceramic electrolytes were improved. The Na3Zr2Si2PO12 ceramic with 5 wt% ATO additive sintered at 1100 °C shows a relatively high ionic conductivity of 1.43 × 10 − 3 S cm-1 at room-temperature, most densest microstructure and wide electrochemical window up to 4.6 V (vs. Na/Na+). In addition, Na/NASICON/Na symmetrical cells were assembled and exhibited good cycling stability which implied good compatibility between sodium (Na) metal and NASICON electrolyte.

Lanthanum silicate oxyapatites with and without calcium (Ca) and iron (Fe) doping, La 10 Si 5 FeO 26.5 (LSFO) and La 9.5 Ca 0.5 Si 5.5 Fe 0.5 O 26.5 (LCSFO), are synthesized by sol–gel process (SGP) and solid state reaction process (SSP). The phase formation, microstructure and conductivities of LSFO and LCSFO oxyapatites are characterized by X-ray diffraction (XRD), scanning electron spectroscopy (SEM) and complex impedance analysis. The morphologies of LCSFO oxyapatite nanoparticles synthesized by SGP were characterized by transmission electron microscope (TEM). The thermal and decomposition properties of the LCSFO gel were analyzed by simultaneous differential scanning calorimetry and thermal gravimetric analysis (DSC–TGA). The results show that the phase formation of LCSFO synthesized by SGP occurs at temperatures as low as 750 °C, significantly lower than ∼1500 °C required for LCSFO synthesized by SSP. Co-doping of Ca and Fe significantly improves the densification, sinterability and oxide-ion conductivity of lanthanum silicate oxyapatites. The best results were obtained on LCSFO synthesized by SGP, achieving oxide-ion conductivity of 2.08 × 10 −2 S cm −1 at 800 °C, which is higher than 5.68 × 10 −3 S cm −1 and 1.04 × 10 −2 S cm −1 for LSFO and LCSFO synthesized by SSP, respectively, under the identical test conditions.

Electroless silver coating of carbonyl iron powder is demonstrated in the present investigation. The carbonyl iron powders are characterized by scanning electron microscope (SEM), energy dispersive X-ray spectroscopy (EDX), and X-ray diffraction analysis (XRD) before and after the coating process. The relatively uniform and continuous silver coating is obtained under the given coating conditions. In this paper, the electromagnetic interference (EMI) shielding mechanism of the silver-coated carbonyl iron powder is suggested. The reflection of silver coating and absorption of carbonyl iron powder dominate the shielding mechanism of the silver-coated carbonyl iron powder. The silver-coated carbonyl iron powders are used as conductive filler in electroconductive adhesive for electromagnetic interference shielding applications. The effect of the thickness of electroconductive adhesive on the shielding effectiveness (SE) is investigated. The results indicate that the SE increases obviously with the increase of the thickness of electroconductive adhesive. The SE of the electroconductive adhesive with 0.35 mm thickness is above 38 dB across the tested frequency range.

Yb:YAG transparent ceramic nano-powder was prepared by chemical co-precipitation method, with ammonium bicarbonate as the precipitant and polyethylene glycol as surfactant. The addition of polyethylene glycol can reduce the agglomeration and particle size of the prepared Yb:YAG powder. The morphology, thermal stability and phase structure of Yb:YAG nano-powder were charactered by scanning electron microscopy (SEM), thermogravimetry and differential thermal analysis (TG-DTA), X-ray diffraction (XRD), and Fourier transform infrared spectroscopy. The results show that well-crystallized nano-powder was obtained by calcining the precursors at 900 °C for 3 h. The average particle size of Yb:YAG powder is about 100–200 nm. When the volume amount of polyethylene glycol is 2.0%, well-dispersed Yb:YAG powder with spherical particles of 100 nm diameter was obtained.

Apatite ceramics are interesting alternative solid oxide fuel cells (SOFCs) electrolytes because of their open structure for the transportation of oxide ions and their good chemical stability. This study reports the influence of barium doping on the microstructure, sinterability and oxide conductivity properties of the aluminium lanthanum oxyapatite La9.5Ba0.5Si5.5Al0.5O26.5. SEM results show that lanthanum substitution with barium improves the sinterability of apatite ceramics. The barium doping also enhances the conductivity of the aluminium lanthanum silicates. The oxygen ion conductivity of La9.5Ba0.5Si5.5Al0.5O26.5 sintered at 1600 °C is 2.21 × 10−2 S cm−1 at 800 °C, higher than 9.81 × 10−3 S cm−1 of La10Si5AlO26.5 sample prepared under the same conditions. The results in the present study demonstrate that doping Ba on the La site for aluminium lanthanum oxyapatite reduces the sintering temperature and improves the ion conductivity. The enhancement of Ba dopant is mainly on the improvement of the densification and thus substantially reduced grain boundary resistance of aluminium lanthanum oxyapatite particularly at low temperatures