- Category: Technology
11 Oct 2012
- Published on Thursday, 11 October 2012 10:03
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A cathode made from inexpensive and abundant manganese and a new electrolyte solution are the key to how Japan’s NEC Corporation improved their battery energy density by approximately 30 percent.
The company currently develops and produces manganese lithium-ion batteries. Their newest prototype features cathodes that support high-voltage operation and an electrolyte solution that improves the stability of high-voltage operations for better energy density and capacity with reduced battery weight.
“These developments can contribute to increasing the driving range of electric vehicles, enabling the production of light weight storage systems and simplifying the management of battery systems by decreasing the number of cells," said Hidenori Shimawaki, general manager of NEC Corporation’s Smart Energy Research Laboratories.
They use manganese-based cathodes with a little nickel and graphite anodes to increase the average operating voltage to 4.5 V.
The new battery increased its energy density by approximately 30 percent to 200 Wh/kg from 150 Wh/kg. This means that they can store 30 percent more energy the existing batteries of the same weight and are 30 percent lighter.
The researchers also changed the solvent in the battery’s electrolyte solution from carbonate-based to fluorinated, making it highly resistant to oxidation. The suppression of oxidative decomposition means that the batteries maintain approximately 80 percent of their original capacity through the charge and discharge cycle.
Tests showed that the batteries maintained 80 percent capacity through 500 full charge and discharge cycles. They are said to have the same operating life as conventional 4V lithium-ion batteries.
NEC will continue to work on the technology to introduce even greater capacity for the batteries and improve their life span and reliability. They are aiming to provide their batteries for use in electric vehicles and large-scale stationary storage applications. – EcoSeed Staff