(Invited) New Viable Nanomaterials for Ultrafast Batteries and Asymmetric Supercapacitors

Monday, 2 October 2017: 08:20
Chesapeake 6 (Gaylord National Resort and Convention Center)
K. Naoi (Tokyo University of Agriculture & Technology)
Hybrid/Asymmetric EESs based on the mechanism of “faradaic” or “extrinsic/intrinsic pseudocapacitive” can certainly overcome the EDLCs’ energy density limitation [3,4,5]. In light of this, K&W/TUAT group developed an original material processing technology called “ultracentrifugation (UC)” that allows to prepare (mass produce) a variety of ultrafast (Li-insertion) nanomaterials capable of 3-7 fold enhancement in energy density. It’ s been demonstrated that UC process typically under 75,000g (with subsequent heat or hydrothermal treatment) gives spinel Li4Ti5O12 nanocrystal as nanosheet/nanobook that are grown on the surface of carbon matrices like MWCNT, SGCNT [1,2,4]. The “nanohybrid capacitor(NHC)” configured as uc-LTO/LiBF4[PC] /AC tripled the energy density of conventional EDLCs [1,3,4]. Nippon Chemi-con Corp. is now eagerly developing commercial NHC device in order to place them in the market. Other uc-derived nanomaterials will be introduced together with their effective utilization in the 2nd gen. “NanoHybrid Capacitor” (JST NexTEP project, 2013-2018) and 3rd gen. “SuperRedox Capacitor” (JST A-step project, 2016-2021). As for LTO alternative anodes, b-axis (ultrashort) controlled 5-nm uc-TiO2(B) [6] and electrochemically activated uc-Li3VO4 [7], both showed ultrafast (300C) charge-storage performances. As cathode, nano-structured 2-cores/1-shell of [uc-LiFePO4(LFP)/amorphous/defective LFP/graphitic carbon] shows ultrafast and symmetric discharge and charge performance (300-480C) [8]. Finally, the author will present a perspective of the future supercapacitors’ market in the world.


[1] K. Naoi, Fuel Cells, 10, 825 (2010).

[2] K. Hata and S. Iijima et al, Science, 306, 1362 (2004).

[3] K. Naoi et al, Energy & Environmental Science, 5, 9363 (2012).

[4] K. Naoi et al, Accounts Chemical Research, 46,1075(2013).

[5] M. Salanne, K. Naoi, and P. Simon et al, Nature Energy, 1, 16070 (2016).

[6] E. Iwama and K. Naoi et al, ACS Nano, 10(5), 5398, (2016).

[7] K. Naoi et al, Advanced Materials, 28, 6751 (2016).

[8] K. Naoi et al, Energy & Environmental Science, 9, 2143 (2016).