Enhanced Li‐ion conductivity of Li7La3Zr2O12 by simultaneous substitution of aluminum and niobium using a modified sol–gel method

Abstract By increasing technical demand for long‐lasting and safer batteries against thermal explosion, garnet‐type cubic phase Li7La3Zr2O12 (LLZO) is a promising solid electrolyte as a next‐generation advanced battery. In this work, we studied Al and Nb co‐doped Li6.25–yAl0.25La3Zr2–yNbyO12 (0 ≤ y ≤ 0.30) electrolytes prepared using a modified sol–gel method. X‐ray diffraction and electrochemical analyses probed the synergistic effect of Al and Nb simultaneous substitution on the microstructure and ionic conductivity. In conclusion, an optimal amount of Al and Nb enhances densification and ionic conductivity, and then Li6Al0.25La3Zr1.75Nb0.25O12 achieves the highest relative density of 94% and total ionic conductivity of 5.41 × 104 S cm−1 at 30°C

Particle Size Control of Pd/C for Improved Electrocatalytic Activity in a Formic Acid Oxidation

Carbon-supported Pd electrocatalyst is prepared by an improved aqueous impregnation method applying a reducing agent of HCHO and an acidic sedimentation promoter of HCl. We investigate the effect of a solution pH on the zeta potential of both Pd particles and carbon support. The opposite sign of zeta potential results in uniform dispersion of Pd on carbon surface without aggregation problem. TEM analysis shows that optimal solution pH of 4.27 adjusted by NaOH provides a mean particle diameter of 3.2 nm with narrow size distribution. Cyclic voltammograms indicate that home-made Pd/C catalyst exhibits significantly higher electrochemical active surface area and better stability compared with commercial 40 wt.% Pd/C in a formic acid oxidation. © 2011 American Scientific Publishers.1

Scalable Synthesis of Few-Layer MoS₂ Incorporated into Hierarchical Porous Carbon Nanosheets for High-Performance Li- and Na-Ion Battery Anodes

It is still a challenging task to develop a facile and scalable process to synthesize porous hybrid materials with high electrochemical performance. Herein, a scalable strategy is developed for the synthesis of few-layer MoS₂ incorporated into hierarchical porous carbon (MHPC) nanosheet composites as anode materials for both Li- (LIB) and Na-ion battery (SIB). An inexpensive oleylamine (OA) is introduced to not only serve as a hinder the stacking of MoS₂ nanosheets but also to provide a conductive carbon, allowing large scale production. In addition, a SiO₂ template is adopted to direct the growth of both carbon and MoS₂ nanosheets, resulting in the formation of hierarchical porous structures with interconnected networks. Due to these unique features, the as-obtained MHPC shows substantial reversible capacity and very long cycling performance when used as an anode material for LIBs and SIBs, even at high current density. Indeed, this material delivers reversible capacities of 732 and 280 mA h g^–1 after 300 cycles at 1 A g^–1 in LIBs and SIBs, respectively. The results suggest that these MHPC composites also have tremendous potential for applications in other fields

Preparation of cost-effective Pt-Co electrodes by pulse electrodeposition for PEMFC electrocatalysts

Low loading platinum-cobalt (Pt-Co) cathode catalyst on a Nafion(Na +)-bonded carbon layer is fabricated by using galvanostatic pulse technique to show the advantage of electrodeposition for high utilization of catalyst in proton exchange membrane fuel cell (PEMFC). We observed that Pt-Co catalysts evenly exist on the surface of carbon electrode and its thickness is about 5.8 μm, which is four times thinner than conventional Pt/C. Improved single cell power performance of Pt-Co cathode catalysts with a ratio of 3.2:1 compared with Pt/C is clearly presented. © 2011 Elsevier Ltd. All rights reserved.