LiBH4 For Safer Solid State Batteries

Scientists have managed to stabilize high-pressure lithium borohydride to create a conducting solid solution that promises safer batteries for the future.

AsianScientist (May 29, 2014) – A team of researchers from Tohoku University in Japan has created a new type of lithium ion conductor using rock salt lithium borohydride (LiBH4), paving the way for the development of new solid state batteries.

Lithium ion batteries are used in applications including medical devices and consumer electronics for their long life. However, they rely on liquid chemistries involving lithium salts dissolved in organic solvents, creating flame risks that could be averted if the cells had been completely solid-state. LiBH4 has been considered for batteries before, but up to now has only worked at high temperatures or pressures.

Through doping a cubic lattice of potassium iodide (KI) with LiBH4, the team managed to stabilize the high-pressure form of LiBH4 and produce a solid solution at normal atmospheric pressure that was stable at room temperature. Additionally, the research, which was published in APL Materials, found that the positively charged Li+ ions in the solid solution functioned like pure Li+ ion conductors despite being used principally for doping.

“In other words, LiBH4 is a sort of ‘parasite’ but not a host material,” explained project leader Hitoshi Takamura, who is associate professor at Tohoku University.

“This work suggests the potential of this mechanism in the ongoing search for the perfect material for use in solid state batteries. The urgency of this quest has been abundantly clear after the grounding of so many aircraft in recent months.”

The article can be found at: Miyazaki et al. (2014) Synthesis of rock-salt type lithium borohydride and its peculiar Li+ ion conduction properties.

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Source: American Institute of Physics; Photo: John Seb Barber/CC/Flickr.
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Alan Aw is a maths enthusiast who likes sharing the fun and beauty of science with others. Besides reading, he enjoys running, badminton, and listening to (and occasionally playing) Bach or Zez Confrey.

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