Daiso and Osaka Prefecture University jointly developed an organic secondary battery expected to be the major candidate to succeed lithium-ion battery. They used an organic compound for the positive-electrode material and opened up the road to realize nearly the same performance achieved by a lithium-ion battery. They built a positive electrode using triquinoxalinylene made up of such substances as nitrogen and carbon. They built a secondary battery using this positive electrode and solid electrolyte instead of liquid electrolyte. The secondary battery built on trial has a capacity close to 80% of a lithium-ion battery, and did not deteriorate performance after 500 times of discharge and charge. They used lithium for the negative electrode this time, but are planning to replace lithium by carbon in the future. Because a battery needs the ability to endure 3,000 times of discharge and charge, practical application of the newly developed technology will be in the late 2020s.
Itaru Honma from Tohoku University and his colleagues built positive and negative electrodes using anthraquione composed of oxygen and carbon. At present, the battery using these two electrodes has only a quarter of capacity of a lithium-ion battery, but it successfully endured 1,000 times of discharge and charge. They predict that increased amount of the organic compound of the two electrodes will allow it to have the same level of capacity as a lithium-ion battery. The battery they envision is scheduled to be put into practical application around 2020. Currently, as the positive electrode of a lithium-ion battery uses lithium and cobalt, the necessary cost to store electric energy at 1 kW/h is about 200,000 yen, four times higher than a lead battery.
Race to develop batteries to succeed lithium-ion battery
Toyota and NTT are now developing an air battery. It has 2-4 more capacity than a lithium-ion battery, and will allow an electric vehicle to travel 400-800 km per charge. The two companies plan to translate it into practical application in the 2030s. Nissan is working on a lithium-sulfur battery that uses lithium and sulfur for the electrodes. It has two times more capacity than a lithium-ion battery, and it does not deteriorate as easily as an air battery. The critical issue is how to overcome the unstable discharge and charge. Practical application is scheduled for 2020.
Sumitomo Electric and Kyoto University are jointly developing a sodium ion battery. The battery they are developing successfully endured 1,000 times discharge and charge at 20 degrees centigrade. A sodium ion battery will be put on the market for the residential storage system to store electricity generated by photovoltaic generation in 2015. Each of Kyoto University and Osaka University is developing a multivalent ion battery that uses magnesium electrode or aluminum electrode. Each of them has already confirmed that it can endure up to 100 times of discharge and charge.
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