P1-2461Highly-porous carbon nanotube sheet for High-Power Lithium-Air BatteryKey Words: Lithium-air battery, High power battery, carbon nanotubeElectric unmanned aerial vehicles (UAVs, like drone, eVTOL) are now widely being developed for establishing new systems of parcel delivery and building inspection. However they are suffered from the short flight times of less than 10-20 minutes. Lightweight and large capacity batteries are needed to extend the flight hour and distance, where Lithium-Air Battery (LAB) can provide a ultimate solution.⚫Highly porous LAB cathode (up to 94% porosity) was developed by CNT⚫Highly porous CNT cathode enhances rate performance of LAB by improving oxygen adsorption⚫LABs operated under atmospheric air (~20% O2) were demonstrated ConclusionLithium-Air BatteryRate & Power performance⚫Research and development of stack cell of LAB, scale up the batter performance, to develop LAB for practical application (drone power source).⚫Developing materials & technology for LAB operation under humid air conditions.Future PlanIntroductionLAB develops high energy density energy storages, exceeding 5-10 times higher energy density than that of Lithium-ion battery (LiB) technology, which can be a power source for UAVs that attain a flight time of 1 hour or more. Despite that, the poor rate performance of LABs hinders the practical development. Highly-porous, air breathable cathodes dramatically enhance the rate capability of LABs. Theme underDiscussionRechargeable Battery Materials Group, GREEN Akihiro NomuraE-mail：： NOMURA.Akihiro@nims.go.jpO2+−Li metalPorous carbonCathodeAnode出力密度/ W kg-1エネルギー密度/ Whkg-1Conventional LABs⚫High energy density, but low power⚫Under pure O2only (Q. Cai et al Journal of Power Sources, 195 6559 2010)012234Voltage / VCapacity / mAh cm-2→ Discharge→ ChargeOCV1st2nd3rd4th5th6th1st4th6thCycleperformance0481223Voltage / V放放電電容容量量/ mAhcm-2C94B87A67Current :0.4mA/cm20123051015Capcity / mAh cm-2Current / mA cm-23.3mAh/cm2@3.0 mA/cm2B87C94A67CNT cathodePorosity /%BET /m2g-1G/DA6767210>100B87878002.9C94946901.810-210-1100101024d(V)/dlog(D) / cm3g-1Pore Diameter, D / mmm10 mmm10 mmmConventional cathode: non-uniform oxygen distributionConventional cathodeOxygen permeable throughout the cathodeCarbon nanotube (CNT) sheet as LAB cathode(NEW)High-porous CNT cathodeCathode pore distributionO2e−Li+Porous carbonelectrolyte/separatorElectrolyteLithium foilLi2O2+－O2+−Li metalPorous carbonSeparator2Li++ 2e−+ O2Li2O22Li 2Li++ 2e−(E = 2.96 V)CathodeAnodeSEM-EDS O element mapDis.CharLi2O2 depositionWeigth：7.7 gEnergy density : 1800 mAh x 2.7V / 8g= 600 Wh/kg10 cell stack (100 cm2electrode area)Highly-Porous CNT sheet cathode develops high rate performance.Our LABs⚫High energy density & high power⚫Under air (~20% O2) OKPower density / W kg-1Energy density / W kg-1DischargeperformanceBatteryperformanceunderdryair(dewpoint:-60~-50ºC)Current :0.4mA/cm2corresponds to ~1C rate of LiB
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