Enhanced ionic conductivity in a novel composite electrolyte based on Gd-doped SnO_(2) nanotubes for ultra-long-life all-solid-state lithium metal batteries

All-solid-state electrolytes are exceedingly attractive because of the outstanding inherent safety and energy density compared to liquid electrolytes.Whereas,it is still formidable to simultaneously design solid electrolytes with favorable electrode/electrolyte interface compatibility and high ionic conductivity in a simple and scalable manner.Hence,the oxygen-vacancy-rich Gd-doped SnO_(2) nanotubes(GDS NTs)are innovatively prepared and applied to the electrolyte of all-solid-state lithium metal batteries for the first time.The addition of GDS NTs can validly construct long-range co ntinuous ion transport networks in the poly(ethylene oxide)(PEO)-based system and greatly improve the mechanical properties of the electrolyte.Compared to the PEO-based electrolyte,the composite electrolyte displays a higher lithium ion conductivity of 2.41×10^(-4) S cm^(-1) at 30℃,a higher lithium ion transference number up to 0.62 and a wider electrochemical window of 5 V at 50℃.In addition,the composite electrolyte manifests outstanding compatibility with high-voltage LiNi_(0.8)Mn_(0.1)Co_(0.1)O_(2)(NMC811)cathode,LiFePO4 cathode and lithium metal anode.The assembled Li/Li symmetric battery exhibits stable Li plating/stripping cycling performance,which can cycle steadily for 1500 h at a capacity of 0.3 mA h cm^(-2).And Li/LiFePO4 battery still maintains a high capacity of 131.54 mA h g^(-1) at 0.5C after 800 cycles,which has a superior capacity retention rate of 93.2%.The obtained novel composite electrolyte has promising application prospects in the field of all-solid-state lithium metal cells.

Structural Analysis and Magnetic Properties of Gd-Doped Li-Ni Ferrites Prepared Using Rheological Phase Reaction Method

A series of Gd-doped Li-Ni ferrites with the formula of LiNi0.5GdxFe2-xO4 where x = 0.00 - 0.08 in steps of 0.02, were prepared by thermolysis of oxalate precursors obtained by rheological phase reaction. The structure, morphology, and the magnetic properties of the samples were characterized by powder X-ray diffraction （XRD）, atomic force microscopy （AFM） and a vibrating sample magnetometer （VSM）. A single spinel phase was obtained in the range of x = 0.00 - 0.04. The lattice parameters of the Gd-doped samples were larger than that of pure Li-Ni ferrite, and increased in the range of 0.00 ≤ x ≤ 0.04, then decreased up to x = 0.08, because of the formation of the secondary phase （Gd- FeO3）. All samples were spheric particles with an average size of about 100 nm, but agglomerated to some extent. The hysteresis loops indicated that the saturation magnetization decreased gradually with increasing Gd content, while the variation of coercivity was related to the microstructure of the Gd-doped samples.

Optimized CeO_(2) Nanowires with Rich Surface Oxygen Vacancies Enable Fast Li-Ion Conduction in Composite Polymer Electrolytes

Low-cost and flexible solid polymer electrolytes are promising in all-solid-state Li-metal batteries with high energy density and safety.However,both the low room-temperature ionic conductivities and the small Li^(+)transference number of these electrolytes significantly increase the internal resistance and overpotential of the battery.Here,we introduce Gd-doped CeO_(2) nanowires with large surface area and rich surface oxygen vacancies to the polymer electrolyte to increase the interaction between Gd-doped CeO_(2) nanowires and polymer electrolytes,which promotes the Li-salt dissociation and increases the concentration of mobile Li ions in the composite polymer electrolytes.The optimized composite polymer electrolyte has a high Li-ion conductivity of 5×10^(-4)4 S cm^(-1) at 30℃ and a large Li+transference number of 0.47.Moreover,the composite polymer electrolytes have excellent compatibility with the metallic lithium anode and high-voltage LiNi_(0.8)Mn _(0.1)Co_(0.1)O_(2)(NMC)cathode,providing the stable cycling of all-solid-state batteries at high current densities.

The Effect of Fabrication Conditions for GDC Buffer Layer on Electrochemical Performance of Solid Oxide Fuel Cells

A Gd-doped ceria（GDC） buffer layer is required between a conventional yttria-stabilized zirconia（YSZ） electrolyte and a La-Sr-Co-Fe-O3（LSCF） cathode to prevent their chemical reaction. In this study,the effect of varying the conditions for fabricating the GDC buffer layer, such as sintering temperature and amount of sintering aid, on the solid oxide fuel cell（SOFC） performance was investigated. A finer GDC powder（i.e., ultra-high surface area）, a higher sintering temperature（1290℃）, and a larger amount of sintering aid（12%） resulted in improved densification of the buffer layer; however, the electrochemical performance of an anode-supported cell containing this GDC buffer layer was poor. These conflicting results are attributed to the formation of（Zr, Ce）O2 and/or excess cobalt grain boundaries（GBs） at higher sintering temperatures with a large amount of sintering aid（i.e., cobalt oxide）. A cell comprising of a cobalt-free GDC buffer layer, which was fabricated using a low-temperature process, had lower cell resistance and higher stability. The results indicate that electrochemical performance and stability of SOFCs strongly depend on fabrication conditions for the GDC buffer layer.

Photocatalytic degradation of bisphenol A using an integrated system of a new gas-liquid-solid circulating fluidized bed reactor and micrometer Gd-doped TiO_2 particles

A new gas-liquid-solid circulating fluidized bed photocatalytic reactor （GLSCFBPR） with internally placed multi-layered UV lamps was developed. Micrometer Gd-TiO2 particles and commercial nanometer P25-TiO2 were chosen as the photocatalysts, and the hazardous substance bisphenol A （BPA） was chosen as the model pollutant to investigate the performance of this new photocatalytic system. The results showed that the photocatalytic degradation efficiency of the micrometer Gd-TiO2 particles was similar to that of the nanometer P-25 particles at their respective optimum dosage but the former could be easily separated out by gravity. After investigating the effects of process parameters on the photocatalytic BPA degradation, the response surface method （RSM） was further used for process optimization. The interactions among process parameters, i.e., TiO2 concentration, superficial gas velocity and superficial liquid velocity were discovered and a related analysis was carried out to explore the underlying mechanism. A quadratic mathematic model was established and performed satisfactorily when used for prediction. The optimum conditions for this new process were as follows： TiO2 concentration 4.5 g/L, superficial gas velocity 7.83 x 10-3 m/sec and superficial liquid velocity 8.65 x 10-3 m/sec.

Effects of NH_3 annealing on interface and electrical properties of Gd-doped HfO_2/Si stack

Effects of NH3 rapid thermal annealing （RTA） on the interface and electrical properties of Gd-doped HfO2 （GDH）/Si stack were investigated. The process of NH3 annealing could significantly affect the crystallization, stoichiometric properties of GDH film and the interface characteristic of GDH/Si system. NH3 annealing also led to the decrease of interface layer thickness. The leakage current density of Pt/GDH/p-Si MOS capacitor without RTA was 2× 10-3 A/cm2. After NH3 annealing, the leakage current density was about one order of magnitude lower （3.9× 104 A/cm2）. The effective permittivity extracted from the C-V curves was -14.1 and 13.1 for samples without and with RTA, respectively.

Synthesis and characterization of Gd-doped PbMoO_(4) nanoparticles used for UV-light-driven photocatalysis

Gd-doped PbMoO_(4) nanoparticles were prepared by a refluxing method at 80℃ for 2 h.Effect of molar content of Gd dopant on phase,morphology and optical properties was studied.The as-prepared Gddoped PbMoO_(4) samples can be indexed to pure tetragonal PbMoO_(4) phase.The particles size of PbMoO_(4) is decreased with increasing in the molar content of Gd dopant from 15.20±3.04 nm for pure PbMoO_(4) to 8.72±1.53 nm for 5 mol% Gd-doped PbMoO_(4).The absorption of 5 mol% Gd-doped PbMoO_(4) nanoparticles shows red-shift caused by lattice distortion of PbMoO_(4).The photocatalytic performance of 5 mol% Gddoped PbMoO_(4) nanoparticles shows the highest degradation of rhodamine B(RhB) of 97.92% under UV radiation and 67.65% under visible radiation because Gd^(3+) dopant as an electron acceptor plays the role in enhancing the separation of electron-hole pair.

Increase in efficiency of dye-sensitized solar cells by porous TiO_2 layer modification with gadolinium-containing thin layer

Modified with gadolinium-containing layer, nanoporous titania electrode and its application in dye-sensitized solar cells were reported. The electrode prepared was characterized with UV-Vis and X-ray diffraction （XRD） techniques. The amount of gadolinium was measured with inductively coupled plasma-optical emission spectrometry （ICP-OES） experiments. The modified electrode showed reduced N3 dye adsorption ability, but increased light conversion efficiency in comparison with the non-modified electrode. The overall conversion efficiencies, determined under 400 W/m2 irradiation with tungsten-halogen lamp at room temperature, were 0.55% for non-modified and 0.74% for modified electrodes.

Microstructure,magnetism and nanomechanical properties of Ni50Mn25Ga20Gd5 magnetic shape memory alloy before and after heat treatment

Polycrystalline Ni50Mn25Ga20Gd5(at%)magnetic shape memory alloy was investigated in the asprepared state and after annealing at 1430 K for 3 h.Microstructural analysis reveals dual-phase nature of the material with substantial distinction between Gd-rich and Gd-poor phases.Magnetic measurements performed in wide range of temperatures confirm reversible martensitic transformation in the annealed sample undergoing close to the room temperature.When it comes to the magnetic transition,the Curie temperature of the investigated alloy remains approximately unchanged at 370 K.Topography investigations conducted on the atomic force microscope in contact mode allow to measure 8 mm difference between minimum and maximum point of the martensite profile.The results from a series of nanoindentation tests show that hardness of the Gd-rich phase is 23%-35%higher than hardness of the Gd-poor phase,depending on the annealing state.