{"id":12079,"date":"2019-03-25T18:06:41","date_gmt":"2019-03-26T01:06:41","guid":{"rendered":"http:\/\/cafe.foundation\/blog\/?p=12079"},"modified":"2019-03-25T18:06:41","modified_gmt":"2019-03-26T01:06:41","slug":"superionic-batteries-are-we-there-yet","status":"publish","type":"post","link":"http:\/\/cafe.foundation\/blog\/superionic-batteries-are-we-there-yet\/","title":{"rendered":"Superionic Batteries \u2013 Are We There Yet?"},"content":{"rendered":"

Tohoku University, near the northern Japanese city of Sendai, finds, in a recent paper,<\/a> \u201c\u2026The development of complex hydride solid electrolytes that exhibit high ionic conductivity at room temperature will be a revolutionary breakthrough for all-solid-state batteries employing a lithium metal anode.\u201d\u00a0 Researchers at the University lists the potential energy density for a battery using these so-called \u201csuperionic\u201d materials as greater than 2,500 Watt-hours per kilogram \u201cat a high current density of 5,016 miliAmps per gram.\u00a0\u00a0 This energy density would result in the fabled 10X battery \u2013 ten times the energy density of a conventional lithium-ion battery \u2013 that has been the subject of international research for the last decade.<\/p>\n

Tohoku\u2019s press release states,<\/a> \u201cScientists from Tohoku University and the High Energy Accelerator Research Organization have developed a new complex hydride lithium superionic conductor that could result in all-solid-state batteries with the highest energy density to date:\u201d\u00a0 Led by Sangryun Kim from the Institute of Material Research (IMR) and Shin-ichi Orimo from the Advanced Institute for Materials Research (AIMR), the study looked for such conductors based on complex hydrides (anions of hydrogen).\u00a0 this is a difficult search, because the potential high energy density of these materials is balanced by the normal instability of the hydrides.<\/p>\n

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High-energy-density all-solid-state lithium metal batteries. a Schematic illustration of the prepared all-solid-state batteries. S, Li\/0.7Li(CB9H10)\u20130.3Li(CB11H12), and lithium metal were used as the cathodes, solid electrolytes, and anodes, respectively. b Voltage profiles for a rate of 0.03\u2009C (50.2\u2009mA\u2009g\u22121) at 25\u2009\u00b0C during the first two cycles. c Discharge\u2013charge profiles at 0.03, 0.05, 0.1, 0.3, and 1\u2009C after an initial cycle at 25\u2009\u00b0C. d Capacity retention as a function of current density. e, f Cycling performances of discharge capacity and coulombic efficiency (e) for a rate of 1\u2009C at 25\u2009\u00b0C and (f) for a discharging rate of 3\u2009C and a charging rate of 1\u2009C at 50\u2009\u00b0C<\/p><\/div>\n

The researchers\u2019 paper, \u201cA complex hydride lithium superionic conductor for high-energy-density all-solid-state lithium metal batteries,\u201d was published in Nature Communications on March 6, 2019.\u00a0 The authors, Sangryun Kim<\/a>,\u00a0Hiroyuki Oguchi<\/a>,\u00a0Naoki Toyama<\/a>,\u00a0Toyoto Sato<\/a>,\u00a0Shigeyuki Takagi<\/a>,\u00a0Toshiya Otomo<\/a>,\u00a0Dorai Arunkumar<\/a>,\u00a0Naoaki Kuwata<\/a>,\u00a0Junichi Kawamura<\/a>\u00a0and Shin-ichi Orimo<\/a>, were able to overcome the high ion transfer resistance found in using solid electrolytes with lithium metal\u00a0anodes.<\/p>\n

The paper is filled with \u201chowevers,\u201d noting the many instances of positive outcomes countered by negative areas of resistance.\u00a0 \u00a0The high energy density possible with superionic conductors was offset by the instability of the solid electrolyte against lithium metal.\u00a0 As the solid electrolyte reaches what we call \u201croom temperatures\u201d it tends to lose contact with the anode and reduce reactivity because the electrolyte is filled with vacancy-rich disordered cation sublattices .\u00a0\u00a0 Researchers managed to tame this with a finer granularity in the material that enables full contact.<\/p>\n

The abstract ends on a promising note: \u201c\u2019We expect that this development will not only inspire future efforts to find lithium superionic conductors based on complex hydrides, but also open up a new trend in the field of solid electrolyte materials that may lead to the development of high-energy-density electrochemical devices,\u2019 \u00a0said Sangryun Kim of Shin-ichi Orimo’s research group at Tohoku University<\/p>\n

Think of a 200-pound battery slimming down to 20 pounds for the same output. Range and \u00a0endurance would be Tesla-like for electric and hybrid aircraft, and following the old rule to two pounds of structure for every pound of power plant for fossil-fuel aircraft, could lead to more efficient airframes.<\/p>\n

At the laboratory stage now, this would seem to be investment bait for venturesome venture capitalists.<\/p>\n