Nippon Chemi-Con (NCC) has reported that using its previously announced ‘nano-hybrid’ technique for electrode production, resulting from academic–industrial collaboration between NCC, the Tokyo University of Agriculture and Technology (TUAT) and an intra-university venture business called K&W Inc, it has succeeded in improving battery electrodes’ volumetric capacity by up to 50%.
‘Nano-hybrid’ is a technique used to obtain composite materials in which various metal oxides in the form of nano-level particles are highly dispersed in a carbon substrate material. By using this technique for the preparation of the anode and cathode materials of next-generation battery cells, NCC and its collaborators have succeeded in producing electrode materials that realise “high output and long life of cells.”
Commonly, carbon materials such as acetylene black are used in lithium-ion cell electrodes to improve their conductivity. When this was replaced with a composite of metal oxides and carbon prepared by this nano-hybrid technique, capacity improved by about 30% with a nano-composite containing lithium manganate (LiMn2O4) and carbon nano-fibres, and by about 50% when a nano-composite containing lithium iron phosphate (LiFePO4) and hollow carbons was used.
This research resulted directly from the work of the Next Generation Capacitor R&D Center established in February this year on the Koganei campus of TUAT.
NCC says two fundamental factors contribute to the increased energy storage capacity of these new lithium-ion electrodes:
- Additional volumetric capacitance was added to the electrode when using the nano-hybrid composites that are capable of storing charge, in place of conductive carbons such as acetylene black that provide essentially no additional charge storage and waste space within the electrodes.
- The density of the nano-hybrid composite materials could be increased within the lithium ion cell electrodes, which when tightly packed improved charge storage with no adverse effects on electrode performance or the electrolyte penetration. In contrast, higher packing densities of acetylene black, etc. result in inhibition of electrolyte penetration and adversely affect electrode performance.
NCC has started supplying samples of these new nano-materials in hope of contributing to the development of ground-breaking high battery capacity and compact cells. The company says the nano-hybrid technique can be applied to a variety of metal oxides and carbon base materials, and in view of the results reported above, is continuing its research efforts to expand the adoption of its new nano-hybrid materials into emerging energy storage applications.
These results were disclosed for the first time at last week’s CEATEC Japan 2012 event in Japan.
