china

Chinese companies Kuraray and Kureha are to produce lithium-ion batteries made from plant-based raw materials at a joint factory in Okayama Prefecture.

Traditionally the anode material comes from graphite but the new factory will use ‘hard carbon’ made from plant materials, including coconut shells.  The effect of using the hard carbon will have a more complex crystal structure than conventional graphite.  This will reduce deterioration occurring because of repeated charge – discharge cycles.

The factory for the joint venture will be built at Kuraray Chemical’s carbon plant and will cost US$ 38 159 000.  Output of the factory should be 1 000 tons of anode material annually.  Building work is due to commence in October with plans for the factory to be operational in Autumn 2013 with plans for expansion already being considered.

Japan is losing out to Chinese and South Korean competitors in supplying lithium-ion battery components around the world. In the 2011 financial year Japan supplied less than half of these key parts.

Global shipments of cathode and anode materials, separators and electrolytes are estimated to have grown 11.2% to US$70.2 million last fiscal year. Japanese firms' share fell 5.7% points to 46.6%, dipping below the 50% mark for the first time since 2008.

The Japanese Yano Research Institute believes Japan’s dominance was weakened following the 2011 earthquake and tsunami that halted the supply of some essential parts around the country. This, combined with the strong yen cutting into Japan’s competitiveness, meant a demand for cheaper materials grew.  Another factor is the shift in South Korean battery manufacturers to use domestically made parts over imports.

A Tohoku University researcher last month announced the development of a lithium-ion battery whose positive electrode does not use any rare earth metals.

Conventional lithium-ion batteries do use rare metals, such as cobalt and nickel, in the positive electrode. Due to their geochemical properties rare earth elements can be dispersed and often not found in concentrated or economically exploitable forms.  This makes these metals costly, and supplies not always stable. Eliminating them will likely make the batteries cheaper to manufacture.

China announced plans in 2009 to reduce its export quota of rare earth minerals to around 350,000 tons per year to conserve scarce resources and protect the environment.  This has led to other countries stock-piling their reserves.  The EU, US and Japan have brought a complaint to the World Trade Organisation alleging China is restricting the exports to maximize domestic use and thus distort the global economy.

Professor Itaru Honma of Tohoku University's Institute of Multidisciplinary Research for Advanced Materials has succeeded in replacing these metals with organic substances. As a result, costs of materials for the positive electrode have been slashed to less than one-fifth what they were before.

Professor Honma made a button-sized lithium-ion battery for testing. This prototype achieved an energy density of 200 watt-hours per kilogram -- roughly double that of current lithium-ion batteries. Tests confirmed that the button-sized battery could withstand at least 100 charge-discharge cycles.

The next step will be to look further for organic materials that more efficiently store power and boost the battery's capacity, with a goal of developing a secondary battery for electric vehicles.