It is used in the development and research of lithium battery anode composites
- Jan 08, 2020-
Currently, the cathode materials used in commercial lithium ion batteries are all carbon materials, including graphitized carbon materials such as graphitized mesophase carbon microbeads and some pyrolysis hard carbon.At present the real specific capacity of the carbon material is generally not more than 400 ma · h/g, although than currently used most of the anode materials of specific storage (typically 120 ~ 180 ma · h/g) were high, but because of the low tap density of carbon materials, combined with general negative set fluid using the copper foil and the positive use lighter aluminum foil, so the volume of the anode material actual given the positive rather than negative.Therefore, to further improve the specific energy of the battery, improve the performance of lithium embedded anode material is the key to research and development.And with the increasing popularity of electronic products, the need for high specific energy batteries is increasing.At present, a single material can not fully meet the relevant needs.Although carbon material has good cycling performance, it is lower than capacity.Other electrochemical properties of carbon materials with higher capacity are impaired.Alloy materials have high specific energy, but due to the large volume expansion in the process of lithium embedding, the cyclic properties of the materials are far from meeting the requirements.Tin - based composite oxides have good cycling characteristics, but the first irreversible capacity loss has not been solved.In this way, it is a reasonable choice to combine the advantages of various materials, purposefully compound various materials to avoid their own shortcomings, and to form composite cathode materials. At present, the research on composite materials has achieved certain results.
In view of the first irreversible capacity loss of materials, it has been proposed to use transition metal nitride containing lithium to compensate, and lithium and tin oxide reaction to solve the first irreversible capacity loss of tin oxide materials.
In view of the poor circularity of alloy materials, the idea of dispersing one active material into another inactive material to form composite materials has been proposed.Such efforts include Thackeray et al. 's proposal to improve the electrochemical cycling of cu-sn alloys by utilizing inert grids formed by excess copper.HisashiTamai et al. made use of organotin to prepare nanoscale tin composites dispersed in carbon grids to improve the circulability of materials.Such as the preparation of graphite tin composites by ball grinding;The conductive polymer/metal alloy composites were studied.Carbon was coated on the surface of silicon particles by CVD method, and it was found that the electrochemical cycling of silicon was greatly improved after surface coating.The conductive polymer and lithium alloy composite electrode were prepared.All of these obviously improve the electrochemical cycling of the alloy materials.