Generalized staircase model of electrochemical impedance of pores in supercapacitor electrodes

Представлена новая обобщенная лестничная модель электрохимического импеданса для пористых материалов электродов в устройствах хранения энергии. Дано краткое описание существующих моделей межфазного импеданса и их ограничений. Новая модель основана на общепринятой “лестничной” модели импеданса цилиндрических пор. Однако новая модель учитывает сложную пористую структуру электродных материалов. В частности, модель описывает импеданс электродов с иерархической пористой разветвленной структурой, в которой широкие поры разветвляются в более узкие. Новая модель позволяет вычислить импеданс межфазной границы электрод/электролит в присутствии как нефарадеевских, так и фарадеевских процессов. Модель успешно опробована для пор с простой геометрией, для которых существуют точные решения. Изучено влияние структурных параметров модельных пористых электродов на их характеристики работы в суперконденсаторах. Проанализировано влияние диаметра пор, величины расширения начал пор и разветвления пор. Сформулированы критерии направленного дизайна электродных материалов для суперконденсаторов A new generalized staircase model of the electrochemical impedance is presented for porous electrode materials in energy storage devices. A brief overview on existing models of interfacial impedance and their limitations is given. The new model is based on the conventional staircase model of the impedance in cylindrical pores. However, the new model takes into account the complex porous structure of electrode materials. In particular, the impedance of hierarchical branching porous electrodes is described, i.e. the wide pores branching into the narrower pores. The new model allows to evaluate the impedance of the electrode/electrolyte interface in the presence of both non-faradaic and faradaic processes. The model is validated using the available exact solutions and experimental data for simple pore geometries. The influence of the parameters of structure of model porous electrodes on their performance in supercapacitors is studied. In particular, the influence of the diameter of the pores, width of pore openings, branching of pores is analyzed. The guideline for focused design of electrode materials of supercapacitors is outlined

The Preparation And Electrochemical Performance Analysis of Different Porous Silicon Composites

In this work, LiAlH4 is used to reduce SiO2 to porous silicon, and then nano-silver (AgNPs) and Li2CO3 are attached to porous silicon substrate to form different porous silicon composites. X-ray diffraction (XRD) and scanning electron microscopy (SEM) are applied to characterize the morphology of porous silicon composites, and porous silicon composites are tested via electrochemical techniques. The experimental results present that porous silicon composites loaded with AgNPs (Si-Ag) show higher specific capacity (476.0195 mA·h·g-1) and lower interfacial impedance compared with composites loaded with Li2CO3 (Si-Li2CO3). Si-Ag composites are suitable to be used as anode materials for lithium-ion batteries.

An In Situ Generated Polymer Electrolyte via Anionic Ring-Opening Polymerization for Lithium-Sulfur Batteries

The use of solid polymer electrolytes has previously proven to be an effective approach to address the lithium polysulfide dissolution and high electrode interfacial impedance of Li-S batteries via an...

Polyaniline coating electrochemical properties improvement after roughened platinum substrate and its anti-wear performance study

In order to improve the electrochemical performance of the neural electrode the polyaniline coatings were modified on roughened Pt (PANI/rPt1) electrodes using electrochemical method. The roughness factor (fR up to 424) of Pt surfaces increased significantly through electrochemical roughening processing. PANI/rPt electrodes showed excellent interfacial properties. Specifically, about 5.6-fold increase in the charge density of PANI/rPt (fR = 424) was observed, while the interfacial impedance (103.5 Ω) was reduced by 50% compared to that of PANI coatings on the smooth Pt surfaces (PANI/sPt2). The results indicate the potential application of PANI/rPt as an efficient and stable future neural interface. In addition, the wear test shows that the coating did not fail during the wearing period and holds an excellent wear resistance ability.

Engineering the ABIO-BIO interface of neurostimulation electrodes using polypyrrole and bioactive hydrogels

Following spinal cord injury, the use of electrodes for neurostimulation in animal models has been shown to stimulate muscle movement, however, the efficacy of such treatment is impaired by increased interfacial impedance caused by fibrous encapsulation of the electrode. Sputter-deposited gold-on-polyimide electrodes were modified by potentiostatic electrodeposition of poly(pyrrole-co-3-pyrrolylbutyrate-conj-aminoethylmethacrylate): sulfopropyl methacrylate [P(Py-co-PyBA-conj-AEMA):SPMA] to various charge densities (0–100 mC/cm2) to address interfacial impedance and coated with a phosphoryl choline containing bioactive hydrogel to address biocompatibility at the ABIO-BIO interface. Electrodes were characterized with scanning electron microscopy (surface morphology), multiple-scan rate cyclic voltammetry (peak current and electroactive area), and electrochemical impedance spectroscopy (charge transfer resistance and membrane resistance). SEM analysis and electroactive area calculations identified films fabricated with a charge density of 50 mC/cm2 as well suited for neurostimulation electrodes. Charge transfer resistance demonstrated a strong inverse correlation (−0.83) with charge density of electrodeposition. On average, the addition of polypyrrole and hydrogel to neurostimulation electrodes decreased charge transfer resistance by 82 %. These results support the use of interfacial engineering techniques to mitigate high interfacial impedance and combat the foreign body response towards epidurally implanted neurostimulation electrodes.

All ceramic cathode composite design and manufacturing towards low interfacial resistance for garnet-based solid-state lithium batteries

Solution-assisted all-oxide-cathode formation method allows reduction of processing temperature without using sintering additives, demonstrating the lowest interfacial impedance in garnet-based solid-state lithium batteries.

Reducing interfacial resistance of a Li1.5Al0.5Ge1.5(PO4)3 solid electrolyte/electrode interface by polymer interlayer protection

Using PPC interlayers to protect the LAGP electrolyte and reduce the interfacial impedance between electrode and electrolyte.