Vol 24, No 3 (2024)
Articles
Nafion-based solid polymer electrolytes for lithium-ion and sodium-ion batteries
Abstract
The use of solid polymer electrolytes is a novel and promising approach for enhancing the safety of lithium-ion and sodium-ion batteries. A number of publications on manufacturing electrolytes with lithium-ion and sodium-ion conductivity based on Nafion-like polymers have appeared in recent decade. The present mini-review analyses various methods of the synthesis of such electrolytes and their properties, as well as the information on laboratory lithium-ion and sodium-ion batteries using such electrolytes. The conclusion is made that the use of Nafion-based solid polymer electrolytes with Li+ and Na+ cation conductivity opens the way to creation of a new generation of lithium-ion and sodium-ion batteries. The principal advantage of Nafion-based solid polymer electrolytes over traditional PEO-based electrolytes is a fairly high cation transport number, which provides a sharp decrease in concentration polarization and, consequently, the increase in the energy efficiency of batteries.
Electrochemical Energetics. 2024;24(3):117-132
117-132
Composite electrodes based on Li3V2(PO4)3, Li4Ti5O12 and carbon nanotubes: The influence of composition, thickness and surface morphology on electrochemical properties
Abstract
The influence of the composition, the thickness and the surface morphology of Li3V2(PO4)3 or Li4Ti5O12 based electrode composites with carbon nanomaterial and polyvinylidene fluoride on their electrochemical performance was examined. The thickness and the surface morphology of the electrodes were jointly controlled by rolling with different gaps and monitored using 3D laser microscopy and scanning electron microscopy. Increasing carbon nanomaterial content, the increase in the specific capacity of the electrode due to the non-Faradic component was observed up to the values of the specific capacity seemingly exceeding the theoretical capabilities of Li3V2(PO4)3 or Li4Ti5O12. When rolling the electrode with decreasing gap, we observed that Li3V2(PO4)3-based electrode composites improved their performance in terms of initial specific capacity and resistance to high current loads. As for Li4Ti5O12-based composites we observed the extremum. We concluded that not only the contact of Li4Ti5O12 or Li3V2(PO4)3 with electrolyte, but the three-phase contact of Li4Ti5O12 or Li3V2(PO4)3 with carbon nanomaterial particles and electrolyte as well was important for the electrochemical activity of electrode composites.
Electrochemical Energetics. 2024;24(3):133-149
133-149
Behavior of electrodeposited silicon film on glassy carbon during lithiation and delithiation
Abstract
Silicon is one of the promising anode materials for lithium-ion batteries with enhanced performance. However, the degradation of silicon during lithiation/delithiation is still the main problem that prevents it commercial use as electrodes. In this work the behavior of a silicon film of about 5–6 µm thick electrodeposited from LiCl-KCl-CsCl-K2SiF6 melt on glassy carbon was studied during its lithiation and delithiation, the film being a part of the anode half-cell of a lithium-ion battery. For this purpose, the methods of cycling in galvanostatic mode, electrochemical impedance, and scanning electron microscopy were used. The principal possibility of lithiation/delithiation of the film was shown and its energy characteristics during multiple cycling were determined. However, during 714 charge-discharge cycles with the current being 0.84 A/g the discharge capacity decreased from 723 to 58 mA·h/g. It was noted that the cause of degradation of the investigated sample was the detachment of the film from the glassy carbon substrate and its cracking.
Electrochemical Energetics. 2024;24(3):150-160
150-160
New cathode material La2/3Cu3Ti4 – xFexO12 – δ for solid oxide fuel cell: Synthesis and electrical conductivity
Abstract
Copper lanthanum titanate La2/3Cu3Ti4−xFexO12−δ x = 0–1 was doped with Fe3+ cations. The diagram of the dependence of the tolerance factor on the relative electronegativity of cations for all studied compositions was represented. It was shown that all the compositions exist in the region of existence of distorted perovskite. X-ray diffraction and X-ray phase analysis methods established the region of existence of solid solutions of La2/3Cu3Ti4−xFexO12−δ obtained by ceramic technology, which was 0 ⩽ x ⩽ 0.4. The temperature dependences of electrical conductivity for the compositions from the region of existence of solid solutions La2/3Cu3Ti4−xFexO12−δ were obtained. The ionic-electronic nature of conductivity was suggested. It was shown that the decrease of electronic conductivity under the increase of iron content was due to the compensation of electronic carriers formed during acceptor doping.
Electrochemical Energetics. 2024;24(3):161-168
161-168