Determination of Chemical Diffusion Coefficient of Lithium Ions in Ceramics Derived from Pyrolysed Poly(1,2-dimethylsilazane) and Starch

AbstractThe apparent chemical diffusion coefficient Li+ (DappLI+) in pyrolysed poly(1,2-dimethylsilazane)/starch (PSN/S) (weight ratio: 30/70) ceramic anode composite is determined by galvanostatic intermittent titration technique (GITT). The electrode material composition is C6.00N0.14H0.47O0.12Si0.13. The calculated values of DappLI+, depend on the applied potential, vary from 10-14 to 10-9 [cm2/s]. The diffusion coefficient of lithium ions calculated in this work are similar with the values reported by other authors for carbonaceous anodes

Organic-inorganic materials for fast charging-discharging processes in energy storage devices

The electrochemical properties of composite material consisting of poly(3, 4-ethylenedioxythiophene) (pEDOT) and iron hexacyanocobaltate (FehcCo) have been investigated for supercapacitors' application. The composite material pEDOT/FehcCo was electrodeposited on titanium or carbon fabric substrate. Prepared electrodes were used in supercapacitors operating in nonaqueous electrolytes (1 M KPF6, 1 M LiPF6 in ethylene carbonate with dimethyl carbonate mixture of solvents). The capacitance values were estimated by galvanostatic and cyclic voltammetry techniques. The material was investigated in symmetric two-electrode cell configuration. The material pEDOT/FehcCo exhibits high capacitance values (~70 F cm-3) and a good cycling performance with a high stability in the tested electrolytes

The influence of photointercalaction and photochromism effects on the photocatalytic properties of electrochemically obtained maze-like MoO3 microstructures

Molybdenum oxide (α-MoO3) thin films with oriented crystalline facets were synthesised by anodization of Mo foils. The obtained samples were exposed to UV–Vis illumination in aqueous electrolytes providing different cations. The morphology and structure of modified samples were investigated. The effect of photointercalated alkali metal cations (Li+, Na+, K+) on optical and structural properties was studied using UV–vis and Raman spectroscopies, respectively. The observed energy band gap narrowing caused by the photochromic effect is found to affect the photocatalytic properties of the intercalated oxide. The photoactivity of obtained samples was tested during the photocatalytic process of methylene blue decomposition in the presence of 0.1 M Li2SO4, Na2SO4, K2SO4. After 2 h of continuous illumination, the photodecomposition efficiency of MB in the presence of K2SO4, Na2SO4 and Li2SO4 was 67%, 69% and 76%, respectively, whereas when no inorganic salt had been dissolved it reached only 57%.</p

Improving the Performance of a Graphite Foil/Polyaniline Electrode Material by a Thin PEDOT:PSS Layer for Application in Flexible, High Power Supercapacitors

In this study, we present a novel strategy for enhancing polyaniline stability and thus obtaining an electrode material with practical application in supercapacitors. A promising (graphite foil/polyaniline/poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) GF/PANI/PEDOT:PSS) electrode material was characterized and used in the construction of a symmetric supercapacitor that provides an outstanding high power density. For this purpose, the electropolymerization of PANI was carried out on a graphite foil and then a thin protective layer of PEDOT:PSS was deposited. The presence of the nanometer PEDOT:PSS layer made it possible to widen the electroactivity potential range of the electrode material. Moreover, the synergy between materials positively affected the amount of accumulated charge, and thus the thin PEDOT:PSS layer contributed to enhancing the specific capacity of the electrode material. The electrochemical performance of the GF/PANI/PEDOT:PSS electrode, as well as the symmetrical supercapacitor, was investigated by cyclic voltammetry and galvanostatic charge/discharge cycles in 1 M H2SO4 at room temperature. The fabricated electrode material shows a high specific capacitance (Csp) of 557.4 Fg−1 and areal capacitance (Careal) of 2600 mF·cm−2 in 1 M H2SO4 at a current density of 200 mA·cm−2 (~4 A·g−1). The supercapacitor performance was studied and the results show that a thin PEDOT:PSS layer enables cycling stability improvement of the device from 54% to 67% after 10,000 cycles, and provides a high specific capacity (159.8 F·g−1) and a maximum specific power (18,043 W·kg−1) for practical applications