Materials for Rechargeable Batteries
Development and Testing of Nanostructured Oxide Materials for Rechargeable Lithium-Ion Batteries
Tech Area / Field
- MAT-SYN/Materials Synthesis and Processing/Materials
- PHY-SSP/Solid State Physics/Physics
3 Approved without Funding
Institute of Microelectronics Technology and High Purity Materials, Russia, Moscow reg., Chernogolovka
- MISIS (Steel and Alloys), Russia, Moscow
- Universität Ulm / Central Facility of Electron Microscopy, Germany, Ulm
Project summaryRechargeable lithium-ion batteries are now one of most widely used power supplies for portable electronic devices. Their mass application is due to good operational characteristics including high power capacity and good cycling. The fields of application of lithium-ion batteries are observed to extend to both the design of large-scale power devices (power sources for electric vehicles and energy storage systems) and the design of microbatteries used in microsystem technics. Therefore, the urgent important task is further enhancement of power capacity and other operational characteristics of available lithium-ion batteries. In majority of lithium-ion batteries made now lithium cobalt oxide is used as a cathode material. This material is rather expensive and toxic because of cobalt contained in it. Probable wide application of lithium-ion batteries in powerful power devices even more emphasizes the problems of their reduction in price and environmental protection. From the point of view of cost and ecological compatibility potentially beneficial cathode materials are lithium nickel and especially lithium manganese oxides. However electrical characteristics of nickel and manganese oxide batteries prepared by the known technological procedures are inferior to those of cobalt-containing batteries on such parameters as power capacity and cycling.
Oxide materials used now are of polycrystalline form with micrometer-sized (1-10 μm) particles. There are some potential ways to increase the characteristics of batteries by the use of a cathode material which will be formed of crystallites of nanometer size. These opportunities can be caused by that:
- a nanostructured cathode material might withstand cyclic mechanical tension arising due to changes in a crystal lattice with lithium intercalation and deintercalation more easily that can lead to improvement of batteries cycling;
- oxide nanoparticles can provide for a higher degree of their intercalation by lithium for a shorter period of time as a result of shorter distances of lithium ions diffusion that may result to an increase of power capacity and reduction of charging time;
- the big area of contacts at use of nanostructured oxides also assumes an opportunity to raise charge and discharge rate of the battery; and, at last,
- nanostructured state of oxide materials may be favorable for new electrochemical reactions which do not occur in volume material and can be basis for enhanced characteristics of the batteries.
An overall objective of the present work is the development of methods of the synthesis of nanoparticles of lithiated Co, Ni, and Mn oxides and their solid solutions to form cathode materials for lithium-ion batteries with high electrochemical characteristics. The problem of potential risks which may not allow achieving expected advantages of use nanostructured cathode materials will be studied during this work as well. Potential risks include
- possible reduction of specific capacity of batteries unless special methods to compact nanostructural oxides will be developed; and
- increases in probability of undesirable reactions at border an electrode/electrolyte due to essentially increased interface area. The existence of potential risks can specify that the best characteristics of batteries can be reached at the certain contents of nanomaterials with the preset size of oxide particles.
The general working schedule for project realization includes:
1. Development of new methods for the synthesis of nanostructured oxides with controllable particle size:
- investigating the possibility of low temperature synthesis using ultrasound dispersion of starting mixtures of reagents;
- searching for new gel-forming media to be used in sol-gel syntheses;
- testing new fluxing materials for low temperature syntheses of desired compounds.
- conditions for the formation of the high temperature phase at low temperature syntheses;
- cationic composition of nanoparticles versus reaction temperature, time of heat treatment, and reagent ratio of starting mixtures;
- stability of the phases obtained by various methods at extreme extraction of lithium and the determination of a limiting degree of extraction, provided a retention of the initial structure.
- testing ion-conducting binding components which prevent aggregation of nanoparticles into large size particles;
- developing compaction methods to achieve high specific capacity of nanomaterials;
- studying electrochemical characteristics of cathode materials on dependence of percentage of nanomaterial and particle size;
- studying the influence of doping by transition and non-transition metals, which substitute cobalt, nickel and manganese in cathode material, on stability of resulted compounds;
- studying the effect of reagent purity (content of controllable and random admixtures) on stability of working parameters of the final product.
The International Science and Technology Center (ISTC) is an intergovernmental organization connecting scientists from Kazakhstan, Armenia, Tajikistan, Kyrgyzstan, and Georgia with their peers and research organizations in the EU, Japan, Republic of Korea, Norway and the United States.
ISTC facilitates international science projects and assists the global scientific and business community to source and engage with CIS and Georgian institutes that develop or possess an excellence of scientific know-how.