The TiO2-Modified Separator Improving the Electrochemical Performance of Lithium-Sulfur Battery

Electrochemical performance of activated carbon/sulfur composite cathode in the Li-S cell with standard and TiO2-modified separator is evaluated by cyclic voltammetry and galvanostatic chronopotentiometry. The modification of the separator by TiO2 impregnation has beneficial effect on the charge capacity of the activated carbon/sulfur cathode in the Li-S cell. The specific capacity of the cathode in the cell with TiO2-modified separator is 632 mAh g-1 (calculated from cyclic voltammetry) and 673 mAh g-1 (determined from galvanostatic chronopotentiometry). Facile impregnation of the separator with nanocrystalline TiO2 results in the 10-20 % stable increase of the charge capacity of corresponding activated carbon/sulfur cathode as compared to its electrochemical performance in the system with non-modified separator.

Nanocarbon-Iridium Oxide Nanostructured Hybrids as Large Charge Capacity Electrostimulation Electrodes for Neural Repair

Nanostructuring nanocarbons with IrOx yields to material coatings with large charge capacities for neural electrostimulation, and large reproducibility in time, that carbons do not exhibit. This work shows the contributions of carbon and the different nanostructures present, as well as the impact of functionalizing graphene with oxygen and nitrogen, and the effects of including conducting polymers within the hybrid materials. Different mammalian neural growth models differentiate the roles of the substrate material in absence and in presence of applied electric fields and address optimal electrodes for the future clinical applications.

Battery Management for Small Hydroponic Systems and Cultivation Experiments

A small hydroponic system that can use sustainable energy such as solar power has been developed. However, the amount of power generated is not constant, and in the case of unstable weather, enough power cannot be obtained. Therefore, it is necessary to store the generated energy in a battery. In order to design low-cost charging equipment, it is necessary to use a smaller battery and to estimate the remaining charge capacity (state of charge: SOC) accurately. To provide an accurate SOC estimation for such systems, a fusion of CI (current integral) and OCV (open circuit voltage) methods is proposed. When using this method, it is necessary to frequently disconnect the electronic load. In these experiments, the optimum disconnection duration, the effects on plants of frequent battery disconnection, and cutting off of the lighting were investigated.

Preparation of xLi2MnO3·(1-x)(LiMn1/3Co1/3Ni1/3)O2 cathode material and its electrochemical properties for Li-ion batteries

The layered xLi2MnO3·(1-x)(LiMn1/3Co1/3Ni1/3)O2 (x = 0.15, 0.3, 0.45) as cathode materials in Li-ion batteries were prepared by co-precipitation of hydroxides. The effects of sintering duration, chemical composition and temperature on the structure and electrochemical performance were studied. The results show that the 0.3Li2MnO3·0.7(LiMn1/3Co1/3Ni1/3)O2 material prepared at 800 °C for 20 h has higher crystallization degree and better electrochemical performance. The charge capacity in the first circle was 359.8 mAh·g-1, the discharge capacity was 240.3 mAh·g-1, the discharge efficiency was 66.8% and the capacity retention was also 97.6% after 20 cycles.

Effect of RF magnetron sputtering parameters on the optimization of the discharge capacity of ternary lithium oxide thin films

The increasing demand for lithium-ion batteries has stimulated the investigation of new compounds in order to reduce the costs and the toxicity of their cathodes. Materials constituted of ternary lithiated oxide compounds are a successful alternative to cobalt-rich cathodes. The main disadvantage of ternary compound materials (TCM) is that the maximum amount of electrical charge is only achieved at high redox potentials, a limiting factor if we consider the current development in electrolyte technology. In this work, we investigated the influence of sputtering deposition parameters on the charge capacity of TCM thin films, restraining their electrochemical potential to conventional values. To do so, we analyzed the impact that small changes in crystalline and morphological structures have on the charge capacity at low cell potentials. For this, we performed the RF magnetron sputtering of TCM thin films, and carried out a factorial design of experiments to investigate their electrochemical properties, while limiting the charging potential to 4.20 V vs. Li|Li+. The films were deposited onto a rigid and conductive substrate with different parameters (power and pressure at room temperature). Electrochemical results showed that the discharge capacity is strongly influenced by the deposition parameters, reaching 250 mAh g− 1 even at 4.20 V vs. Li. This value is superior to the ones of the conventional cobalt cathode and the bulk ternary electrode. Both deposition parameters exhibited a synergic dependency, which means that they need to be simultaneously varied for a response optimization. The discharge capacity of the analyzed samples was highly affected by the surface morphology of the film and its crystallographic properties, and not by its elemental composition. High discharge capacity was obtained without additional thermal treatments, which favors the manufacture of films over polymeric substrates for future electronic applications.

Studies on the deposition of copper in lithium-ion batteries during the deep discharge process

End-of-life lithium-ion batteries represent an important secondary raw material source for nickel, cobalt, manganese and lithium compounds in order to obtain starting materials for the production of new cathode material. Each process step in recycling must be performed in such a way contamination products on the cathode material are avoided or reduced. This paper is dedicated to the first step of each recycling process, the deep discharge of lithium-ion batteries, as a prerequisite for the safe opening and disassembling. If pouch cells with different states of charge are connected in series and deep-discharged together, copper deposition occurs preferably in the cell with the lower charge capacity. The current forced through the cell with a low charge capacity leads, after lithium depletion in the anode and the collapse of the solid-electrolyte-interphase (SEI) to a polarity reversal in which the copper collector of the anode is dissolved and copper is deposited on the cathode surface. Based on measurements of the temperature, voltage drop and copper concentration in the electrolyte at the cell with the originally lower charge capacity, the point of dissolution and incipient deposition of copper could be identified and a model of the processes during deep discharge could be developed.

Nanocrystalline TiO2/Carbon/Sulfur Composite Cathodes for Lithium–Sulfur Battery

This paper evaluates the influence of the morphology, surface area, and surface modification of carbonaceous additives on the performance of the corresponding cathode in a lithium–sulfur battery. The structure of sulfur composite cathodes with mesoporous carbon, activated carbon, and electrochemical carbon is studied by X-ray diffraction, nitrogen adsorption measurements, and Raman spectroscopy. The sulfur cathode containing electrochemical carbon with the specific surface area of 1606.6 m2 g−1 exhibits the best electrochemical performance and provides a charge capacity of almost 650 mAh g−1 in cyclic voltammetry at a 0.1 mV s−1 scan rate and up to 1300 mAh g−1 in galvanostatic chronopotentiometry at a 0.1 C rate. This excellent electrochemical behavior is ascribed to the high dispersity of electrochemical carbon, enabling a perfect encapsulation of sulfur. The surface modification of carbonaceous additives by TiO2 has a positive effect on the electrochemical performance of sulfur composites with mesoporous and activated carbons, but it causes a loss of dispersity and a consequent decrease of the charge capacity of the sulfur composite with electrochemical carbon. The composite of sulfur with TiO2-modified activated carbon exhibited the charge capacity of 393 mAh g−1 in cyclic voltammetry and up to 493 mAh g−1 in galvanostatic chronopotentiometry. The presence of an additional Sigracell carbon felt interlayer further improves the electrochemical performance of cells with activated carbon, electrochemical carbon, and nanocrystalline TiO2-modified activated carbon. This positive effect is most pronounced in the case of activated carbon modified by nanocrystalline TiO2. However, it is not boosted by additional coverage by TiO2 or SnO2, which is probably due to the blocking of pores.

Electrochemical performance and reaction mechanism investigation of V2O5 positive electrode material for aqueous rechargeable zinc batteries

The electrochemical performance and reaction mechanism of orthorhombic V2O5 in 1 M ZnSO4 aqueous electrolyte are investigated. V2O5 nanowires exhibit an initial discharge and charge capacity of 277 and 432...