lithium-ion batteries

The reversible insertion of lithium into electrodes based on amorphous boron has been studied. The reversible capacity upon the lithium insertion has been found to be about 750 mA⋅h/g. The most efficient in terms of specific capacity are the electrodes containing graphene as a conductive additive.

The second part of the review describes the prospects of using alternative polymer binders for composite electrodes of lithium electrochemical systems. Possible options having been taken into account, the most popular commercially-available synthetic polymers with functional group (the ones forming aqueous solutions or dispersions predominantly) and water-soluble polymers of natural origin are considered. The versatility of such materials is their distinctive feature.

The current situation in technology and developments in the field of polymer binders for composite electrodes of lithium electrochemical systems are discussed. A wide range of synthetic and natural polymers used for this purpose is considered. Emphasis is placed on commercially available materials, which form aqueous solutions or dispersions. The advantages of multifunctional polymer binders are demonstrated.

The review of cathode materials for lithium-ion batteries is presented, the analysis of advantages and application prospects of cathode materials on the basis of lithiated transition metals oxides is carried out. A method of heterovalent modification by ions of highly negative elements, lanthanum and its analogues for improving the electrochemical indices and stability of lithium manganese spinel is proposed. The effectiveness of fullerene, lithium fluoride, fullerenes halogen derivatives as modifying additive for MnO₂ cathode materials has been noticed.

DOI: https://doi.org/10.18500/1608-4039-2017-17-2-61-88

The critical analysis of literature of last 15 years, concerning features of low-temperature behavior of lithium-ion batteries is presented. Some generalized approaches to the problem as well as the role of main polarization components at low temperatures; features of functioning of negative and positive electrodes are reviewed. Some low-temperature electrolytes are reviewed as well.

DOI: https://doi.org/10.18500/1608-4039-2017-17-1-19-28

On basis of analysis of literature data as well as of own experimental results we suggest some regularity for degradation of silicon electrodes upon cycling. It was shown that an electrode capacity Q at n-th cycle can be calculated from equation Q = Q₀ exp(kn+βn²/2), where Q₀ is initial capacity value, k и β are empiric constants.

Cycling tests of lithium-ion batteries in wide temperature and load ranges have been carried out. The existence of certain threshold discharge load corresponding abrupt decrease of discharge capacity was found.

Discharge behavior of lithium nano-titanate samples synthesized by solid-state methods from titania (anatase) and various lithium compounds has been studied. The shape of discharge curves was shown to change along with increasing current. This change was explained with due account for the model of heterogeneous lithium nano-titanate grain. It is found that the dependence of discharge capacity on current density does not obey to common Peukert equation but consists of two segments. In any cases the exponent in the Peukert equation does not exceed 0.2.