Japanese Researchers Develop Flame-Retardant Electrolyte for Safer Batteries

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The University of Tokyo, Kyoto University, and Japan's National Institute for Materials Science (NIMS) announced on November 28, 2017, that they have developed a fire-extinguishing organic electrolyte as an alternative to conventional flammable organic electrolytes used in lithium-ion batteries and other charging and discharging secondary batteries. The new electrolyte is expected to help accelerate the development of strong, long-lasting batteries with significantly better safety performance.

While much research has gone into realizing higher energy densities in the secondary batteries used in everything from electric vehicles to smart grids, the conventional flammable organic electrolytes used in these batteries carry a high risk of ignition and explosion. Thus, a new approach to securing battery safety is strongly needed.

The new salt-concentrated electrolyte is composed of only a flame-retardant solvent and salt and is therefore resistant to flames. Moreover, when the temperature of the electrolyte rises to over 200 degrees Celsius, it generates steam, which serves as a fire-extinguishing agent. These characteristics can significantly reduce the risk of batteries ignition, and have already been achieved with electrolytes that do not contain any flammable carbonic acid ester solvents.

Carbonic acid ester solvents were once considered essential to the stable functioning of the carbonaceous anode in batteries, but the researchers have demonstrated that their new electrolyte is capable of more than 1,000 charging-discharging cycles with negligible electrode degradation, whereas the capacity of sodium ion cells using a conventional electrolyte was significantly reduced after more than 100 cycles. It has also been confirmed that the new electrolyte is highly compatible with cathode and sufficiently tolerant of voltage, which indicates the possibility of longer-lasting batteries.

Japan Adopts Basic Strategy to Realize Hydrogen-Based Society

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The Japanese government formulated on Dec. 26, 2017, a basic strategy for promoting hydrogen use and becoming a world-leading hydrogen-based society. The strategy, which includes a future vision for the year 2050 and an action plan through 2030, seeks to reduce the cost of carbon-free hydrogen to that of conventional fuels, thus leading the global push toward carbon neutrality.

The strategy calls for establishing a commercial-scale hydrogen supply chain that will see about 300,000 tons of hydrogen purchased annually for 30 yen/Nm3 (about US 26 cents), less than one-third its current cost, by 2030, and as low as 20 yen (about US 18 cents) beyond that. Renewable energy and untapped energy sources from abroad will be utilized to achieve these targets.

The strategy also aims to put hydrogen-generated electricity into commercial use at a cost of 17 yen/kWh (about US 15 cents) by 2030, using about 300,000 tons of hydrogen annually (at a generation capacity of one million kilowatts); the goal thereafter is to expand these to five million and then up to ten million tons (15 million to 30 million kilowatts), at a cost of 12 yen/kWh (about US 11 cents).

Presently, about 2,000 fuel cell vehicles are on the road in Japan and the government intends to increase the number to 800,000 by 2030, simultaneously increasing the 100 hydrogen fuel stations to 900. It also aims to ramp up Ene Farm residential fuel cell units from 220,000 units to 5.3 million units by 2030.