Pt/NiO Microsphere Composite as Efficient Multifunctional Catalysts for Nonaqueous Lithium-Oxygen Batteries and Alkaline Fuel Cells: The Synergistic Effect of Pt and Ni

Developing efficient and low-cost multifunctional electrocatalysts is important for electrochemical devices. In this work, a cost-effective Pt/NiO composite with very limited Pt loading (from 0.5 to 3%) was controllably synthesized through facile hydrothermal procedures. The composite demonstrated the improved catalytic performance as applied to the nonaqueous Li-O₂ batteries and the alkaline fuel cells. Regarding the alkaline fuel cells, 1% Pt/NiO composite gave rise to the best Pt distribution and thus exhibited the optimized electrochemical conductivity and properties as suggested by the significantly improved electrochemical reversibility. Meanwhile, the demonstrated 1% Pt/NiO composite presented high catalytic capability as electrode for Li-O₂ batteries, which allowed for much improved capacity utilization, high cycling stability, high initial capacity (2329 mAh/g), and no obvious voltage drop during cycling. Such multiple advantages of prepared composite electrode material offer new prospects and application as multifunctional electrocatalysts for both Li-O₂ batteries and alkaline fuel cells.

An efficient, bifunctional catalyst for lithium–oxygen batteries obtained through tuning the exterior Co2+/Co3+ ratio of CoOx on N-doped carbon nanofibers

CoO_x NPs@N-doped carbon nanofibers were obtained by an electrospinning technique and served as an excellent catalyst for Li–O₂ cells. The enhanced electrochemical performance can be ascribed to the rich Co²⁺ toward the ORR and OER on the surface of CoO_x.

Excellent oxygen evolution reaction of NiO with a layered nanosphere structure as the cathode of lithium–oxygen batteries

A layered nanosphere structured NiO catalyst was successfully synthesized by a simple and efficient hydrothermal method as a cathode material for lithium–oxygen (Li–O₂) batteries. Cyclic voltammetry (CV), dual electrode voltammetry (DECV) and chronoamperometry (CA) by rotating ring-disk electrode (RRDE) were carried out to investigate the catalytic activity of this catalyst for the oxygen evolution reaction (OER). The results revealed that the layered nanosphere NiO exhibited excellent electrochemical performance, stability and a typical four-electron reaction as a cathode electrocatalyst for rechargeable nonaqueous Li–O₂ batteries. The overpotential of the NiO is only up to 0.61 V. X-ray photoelectron spectroscopy (XPS) characterization shows that the Li₂O₂ and Li₂CO₃ formed during the discharge process and decomposed after charging. Moreover, the cut-off voltage of discharging is about 2.0 V in the NiO-based Li–O₂ batteries, while the specific capacity is up to 3040 mA h g⁻¹. There is no obvious performance decline of the battery after 50 cycles at a current density of 0.1 mA cm⁻² with a superior limited specific capacity of 800 mA h g⁻¹. Herein, the layered nanosphere structured NiO catalyst is considered a promising cathode electrocatalyst for Li–O₂ batteries.

A layered nanosphere structured NiO catalyst was synthesized by a simple and efficient hydrothermal method as a cathode material for lithium–oxygen (Li–O₂) batteries.

Mn doped porous cobalt nitride nanowires with high activity for water oxidation under both alkaline and neutral conditions

We report the successful synthesis of Mn doped CoN nanowires on a carbon fiber cloth substrate (CFC) by a two-step strategy, which can be used as an efficient and stable OER electrocatalyst under both alkaline and neutral conditions.