lithium-ion batteries

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.

Germanium is an attractive element for the anodes in lithium-ion battery. The current article discusses the issue of the availability of raw material for the battery industry, particularly in relation to Russia.

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.

A brief analysis of the current situation in the development of lithium-ion batteries in Russia and all over the world has been carried out. The conclusion is made that Russia produces only a basis point of lithium-ion batteries in the world. It is predicted that Russian production of lithium-ion batteries may increase up to 0.2% in the world by 2030.

The flash point tester PE-TVZ was modernized. The sample volume was reduced from 70 to 5 ml. Mixing of the condensed and gas-vapor phases was done simultaneously. The mercury thermometer was replaced by an electronic one. The correctness of the flash point measurement by the modernized device was tested on the samples with the flash point in the range of 25–170°C.

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 review of modem references on new and modified anodic materials for lithium-ion batteries has represented, which was founded with the help of computer keyword searching. The attempt of systematization for methods of synthesis and modification of such materials is made.

Silicon electrodes with regular porous structure were prepared by the photoelectrochemical etching of single-crystal n-type silicon wafers, followed by the removal of the substrate. Electrodes with pores having circular and square section were studied. The porosity was increased via additional oxidation with the subsequent etching of oxide. The electrochemical characteristics of anodes were found to depend on porosity, electrodes with porosity 60-70% possessing maximal capacity for lithium reversible insertion.

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+βn 2 /2), where Q0 is initial capacity value, k и β are empiric constants.