New electrode materials for Li-ion battery anodes
New anode materials have been produced from modified graphite. These electrode materials for lithium-ion secondary battery have been developed on using of natural, metallurgical and synthetic graphites as starting materials. The modified graphite is characterized by high discharge capacity and can be used for preparing anode without binder.
Modification of Inexpensive Graphite for use as Electrode Materials
Graphite from several sources, including natural and metallurgical graphite, is processed using proprietary methods to yield materials used in battery and supercapacitor manufacture. This graphite can be used without binder to make low cost highly efficient electrodes.
Atomic force microscopy (AFM) is one of the analytical tools used by Enerize to monitor the quality and characteristics of processed materials. AFM images of processed graphite for use as electrode material are shown below. The carbon comprising graphite naturally forms into plates and the structure of these plates can be used to optimize processing for specific applications. Graphite in the plates shown here does not contain binder and is used for high performance electrodes such as those shown above. The images represent an approximate one micron square of graphite surface.
Synthesis of MnO2, LiMn2O4 and Based on Ukrainian Raw Materials
Manganese oxide spinels developed by Enerize are ideal as high power density cathode materials for lithium ion batteries that are much safer than conventional cobalt oxide designs.
With growing concern over the safety of the cobalt oxide cathode designs, spinels based of manganese oxides are of growing in popularity as cathode materials in lithium ion batteries. Spinels such as LiMn2O4 are not only less expensive with lower toxicity, but are also intrinsically safer than cobalt oxide cathode materials.
Recent incidents of lithium ion battery fires in laptop computers are of great concern to officials responsible for public safety, and especially for safety on aircraft. One approach to the issue of battery safety is the use of spinels as cathode materials. Spinels are oxides of metals such as manganese iron and zinc that have a three dimensional lattice structure which is more highly conductive than the crystalline structure of cobalt oxide materials.
Enerize is engaged in the development and testing of new spinel materials for use in lithium ion batteries. The new synthesis methods developed for these spinel materials make them lower in cost while maintaining high conductivity and excellent thermal stability. Production capability is currently in the pilot stage.
The spinel was synthesized using high density MnO2 as a starting material. Electrodes based on this spinel, have a bulk density of 2.4 g/cm3, and a specific discharge capacity of 110-130 mAh/g LiMn2O4. The coating technology developed for making the electrodes provides a discharge capacity up to 80 mAh/g (spinel) at a discharge rate of 20C.
Because of their higher bulk conductivity, these spinel materials can yield higher power densities than cobalt oxides. The improved capability for supplying quick bursts of power are makes spinel cathode batteries of great interest in power-hungry applications such as cell phones. Because they are thermally stable and not prone to the thermal runaway reactions associated with cobalt oxide cathode materials, spinel cathodes are intrinsically much safer. One specific objective of the our research activity is the development of additives for increasing stability the of spinel-based Li-ion batteries during storage and cycling make them lower in cost while maintaining high conductivity and excellent thermal stability. Production capability is currently in the pilot stage.