Aleksandr Mordukhaevich Skundin

The cycle life of anode-free lithium batteries is limited by low Coulombic efficiency (CE) of Li deposition/dissolution on the negative current collector due to dendrite growth and poor lithiophilicity of conventional Ti. Here, we applied a highly lithiophilic coating of 2.5 μm thick germanium nanowires (NWs) onto a Ti current collector, which reduced the Li nucleation overpotential from 109 to 22 mV and increased the initial CE from 70

The correlation between the Coulombic efficiency and the change in the residual capacity of electrodes and batteries under conditions without any parallel irreversible reactions was formulated. It was shown that this relationship allows drawing certain conclusions regarding the nature of degradation processes during cycling.

Currently, the main type of electrochemical energy storage devices are lithium-ion batteries, the global production of which amounts to billions of units per year. Further progress in electrochemical energy storage systems may follow two general trends: improvement of existing lithium-ion batteries and design of alternative types of energy storage devices (so-called post-lithium-ion batteries). The former trend is limited by the fact that characteristics of lithium-ion batteries are approaching the theoretical limit. The latter one is concerned with sodium-ion batteries, lithium–air batteries and primary power sources, lithium–sulfur batteries, and redox flow systems. The present review analyzes state-of-the-art in the development of virtually all types of electrochemical energy storage devices, which makes it possible to compare their characteristics and determine the most appropriate applications for each type of device. The bibliography includes 316 references.

When cycling anode-free sodium batteries, unbalanced volumetric changes in opposite electrodes arise. This problem leads to volumetric changes in the whole battery. While charging the negative electrode, the volume increase corresponds to 0.88 cm3/A·h. The current study evaluates the volume decrease while charging the positive electrodes which are based on sodium vanadophosphate, sodium fluorovanadophosphate, sodium hexacyanoferrate, and sodiated iron sulfide Na1.5FeS2. The conclusion is made that having compared the volumetric changes, the energy density and the average discharge voltage of the batteries used in these electrochemical systems, it is impossible to clearly select the optimal version.

For the first time, the electrochemical behavior of sodium vanadium fluorophosphate-based electrodes in carbonate and diglyme electrolytes was compared. It was shown that a 1 M NaPF6 solution in diglyme can be successfully used in anode-free sodium batteries with sodium vanadium fluorophosphate-based cathodes.

The present minireview considers fundamental electrochemistry and its relation to microelectronics. Various solid electrolytes, principally inorganic ones are described, including LiPON, and diverse sulfide and oxide electrolytes. Examples of all-solid-state electrochemical devices important for microelectronics are described and discussed, such as electrochemical gas compressors and gas purification systems, electrochemical gas sensors, including high-temperature ones, as well microbatteries and thin-film batteries.

So-called anode-free sodium batteries represent a very promising version of post-lithium era devices. The present brief review considers their principal features (both advantages and disadvantages). The main problems connected with their development are phenomena of dendrite formation and encapsulation. These problems could be solved via improvement of negative electrode current collectors (enhancing of their sodiophilicity), as well as the electrolytes’ optimization, in particular, for the development of high-quality solid electrolyte interphases (SEI).

The electrochemical behavior of the multicomponent layered oxide LiNi _0.8 Co _0.15 Al _0.05 O ₂ in an electrolyte containing lithium oxalyl difluoroborate LiF ₂ BC ₂ O ₄ as a supporting salt was studied for the first time. It was shown that the total polarization resistance in this electrolyte is noticeably lower than in an electrolyte based on LiClO ₄ in the same solvent, which leads to an increase in the discharge capacity, especially at increased current loads.

All-solid-state anode-free sodium batteries present a special and especially important kind of energy storage device. Unfortunately, the industrial production of such batteries has been absent up to now, although the prospects of their development seem to be rather optimistic. The present mini review considers the fundamental advantages of all-solid-state anode-free sodium batteries as well as challenges in their creation. The advantages of all-solid-state anode-free sodium batteries reveal themselves when comparing them with ordinary sodium-ion batteries, sodium metal batteries, sodium batteries with liquid electrolyte, and their lithium counterparts.