Development of a Lightweight LTO/Cu Electrode as a Flexible Anode via Etching Process for Lithium-Ion Batteries

In recent years, flexible energy storage devices have attracted the growing demand for flexible electronic systems. Therefore, research on reliable electrodes with high mechanical flexibility and good electronic and lithium-ion conductivity has become critical. Carbon-coated Li₄Ti₅O₁₂ (LTO) nanostructures find essential applications in high-performance lithium-ion batteries (LiBs). Nevertheless, the conventional copper current collector with a thickness of several micrometers accounts for a large proportion of the LiB, making the low-energy density LiB with much less flexibility. Here, hundred nm-thick (LTO/Cu) copper foil-LTO nanostructures are fabricated using a scalable and straightforward process which can be assembled into a film into a flexible, lightweight electrode by etching a conventional copper foil to form an ultra-thin copper layer for LIBs (<1 μm). This process provides essential flexibility to the as-prepared electrode and provides template support for simple fabrication. The LiB cell using the novel LTO/Cu as the anode exhibits an energy capacity of 123 mA h/g during 40 charge-discharge cycles at a 0.1C rate. Besides, the coulombic efficiency of the LiB using LTO/Cu remains over 99% after 40 cycles. These results show the uses of this novel anode and its potential in high-density and flexible commercial lithium-ion batteries.

Studying the Effect of Butanol on the Anode Behavior of Copper in Phosphoric Acid Solutions

The anode behavior of the copper electrode immersed in butanol phosphate electrolytes has been studied. The polarization dependences of the electrode allowed us to detect the sections that correspond to the passive and active states of copper and we also established the zone of the combined behavior of the processes of the copper dissolution and oxygen release. It was also established that a butyl alcohol contributes to an abrupt decrease in current densities in the entire region of anode potentials. The addition of butanol conditions the disappearance of current oscillations that can be seen on polarization dependences in phosphate solutions. Evidently, a decrease in the current densities is a consequence of the butanol adsorption on the copper surface and its participation in the formation of passive films. The specific features of the copper passivation in butanol phosphate electrolytes are characterized by the appearance of the explicit current peak that separates active and passive state zones at the ratio of C4H9OН:H3PO4 =1:3.As the alcohol-to-acid ratio increases, the peak gradually decreases. The addition of butanol has no determining influence on the potential value that corresponds to the started oxygen release. Currentefficiency values for the copper dissolution depend on the anode current density ja and the electrolyte composition. An increase in ja results in a decreased current efficiency value. An increase in the С4Н9ОН content has a similar action. Maximum current efficiency values are observed at ja=0.5–2 А∙dm-2, and they correspond to the active copper state. The dependences obtained for the copper dissolution rate allowed us to establish that υрalso increases with an increase in the current density up to ja=20 А∙dm-2. The copper treatment quality depends on the current density and the electrolyte composition. The solutions with the ratio of C4H9OН:H3PO4=2:1fail to provide a high quality treatment; the surface is not glossy and it has grinding traces. A high-quality treatment is observed in the electrolytes with the ratio of C4H9OН:H3PO4 =1:2 and lower. The electrochemical polishing in such solutions results in the glossy copper surface with the smoothed relief and it has no polishing traces.

0D–2D heterostructures as nanocatalysts for self-oscillating reactions: an investigation into chemical kinetics

Ceria-decorated graphene nanocomposites as an efficient catalyst for the oscillatory Belousov–Zhabotinsky reaction.