A Mathematic Model of Gas-diffusion Electrodes in Contact with Liquid Electrolytes

A mathematic model is developed which is applied to analyze the main factors that affect electrode performance and to account for the process of reaction and mass transfer in gas-diffusion electrodes in contact with liquid electrolytes. Electrochemical Thiele modulus φ^2 and electrochemical effectiveness factor η are introduced to elucidate the effects of diffusion on electrochemical reaction and utilization of the gas-diffusion electrode. Profile of the reactant along axial direction is discussed, dependence of electrode potential V on current density J, are predicated by means of the newly developed mathematical model.

Composite polymer electrolyte membranes supported by non-woven fabrics for lithium-ion polymer batteries

Poly(vinylidene fluoride-co-hexafluoropropyle- ne) (PVDF-HFP) is one of the most popular polymers for polymer electrolyte membranes because of its excellent oper- ating characteristics and superior electrochemical properties. The electrochemical performances of polymer electrolyte membrane can be enhanced by evenly dispersing nano-meter SiO2 particles in the polymer. In this paper, non-woven fab- rics were immersed in the mixed solution of PVDF-HFP/ SiO2/butanone/butanol/plasticizer, and then dried in a vac- uum oven to remove the solvents and the plasticizer and to make porous composite polymer electrolyte membranes. The prepared composite membranes supported by non-woven fabrics boast good mechanical strength and excellent elec- trochemical properties: the electrochemical stability window is 4.8 V vs. Li+/Li, and the ionic conductivity is 3.35×10?4 S/cm (around 60% of that of a common PE membrane) at room temperature. The lithium-ion polymer battery assem- bled by the composite membrane exhibits high rate capabil- ity and excellent cycling performance.

A dual-electrolyte system for photoelectrochemical hydrogen generation using CuInS_2-In_2O_3-TiO_2 nanotube array thin film

The utilization of Na2S/Na2SO3 mixture as the electrolyte solution to stabilize sulfide anode in a photoelectrochemical cell for hydrogen evolution generally compromises the current-to-hydrogen efficiency（ηcurrent） of the system. Here, the employment of a dual-electrolyte system,that is, Na2S/Na2SO3 mixture and p H-neutral Na2SO4 as the respective electrolyte solutions in the anode and cathode chambers of a water splitting cell is demonstrated to suppress the photocorrosion of CuInS2-In2O3-TiO2 nanotube（CISIn2O3-TNT） heterostructure, while simultaneously boosts theηcurrent. Although n-type CIS and In2O3 nanoparticles can be easily formed on TNT array via facile pulse-assisted electrodeposition method, conformal deposition of the nanoparticles homogeneously on the nanotubes wall with preservation of the TNT hollow structure is shown to be essential for achieving efficient charge generation and separation within the heterostructure. In comparison to Na2S/Na2SO3 solution as the sole electrolyte in both the anode and cathode chambers, introduction of dual electrolyte is shown to not only enhance the photostability of the CIS-In2O3-TNT anode, but also lead to near-unity ηcurrentas opposed to the merely 20% ηcurrentof the single-electrolyte system.