(Invited) The Molten Air Battery and the Multiple Electron Storage Advantage
Authors: Licht Stuart , Lefler Matthew J. , Johnson Marcus 
Published: February 2020

We’ve demonstrated multiple electron per molecule processes yield higher battery storage capacity, introducing a variety of novel storage chemistries including high efficiency in-situ photoelectrochemical solar cells,1,2 aluminum sulfur battery,3 super-iron battery,4 ammonia useful for fuel cells,5 and zirconia on VB2 batteries.6 Unusual multiple electron opportunities abound. For example, not only redox active oxygen from air, but also redox active carbon dioxide from air can be utilized for charge storage.7,8

The Licht group has recently introduced a new class of multiple electrons per molecule battery: Molten Air Batteries.9-14 These new batteries use multi-electron charge storage, a molten electrolyte, are quasi-reversible (rechargeable), and have amongst the highest intrinsic battery storage capacities. This talk will focus on advances in the molten air class of rechargeable batteries including carbon (4 electron storage), iron (3 electron storage) and VB2 (11 electron storage). For example, uncommonly, the carbon molten air battery can utilize carbon dioxide directly from the air or from industrial smoke stacks:
charging: CO2(g) -> C(solid) + O2(g) (1)
discharging: C(solid) + O2(g) -> CO2(g) (2)
1) S. Licht, G. Hodes, R. Tenne, J. Manassen, A Light Variation Insensitive High Efficiency Solar Cell"

Nature
, 326, 863-864 (1987).
2) S. Licht, "A Description of Energy Conversion in Photoelectrochemical Solar Cells"

Nature
, 330, 148-151 (1987).
3) D. Peramunage, S. Licht, "A Novel Solid Sulfur Cathode for Aqueous Batteries"

Science
, 261, 1029-1032 (1993).
4) S. Licht, B. Wang, S. Ghosh, "Energetic Iron(VI) Chemistry: The Super-Iron Battery,"

Science
, 285, 1039-1042 (1999).
5) S. Licht, B. Cui, B, Wang, F.-F. Li, J. Lau, S, Liu, "Ammonia synthesis by N2 and steam electrolysis in molten hydroxide
suspensions of nanoscale Fe2O3,"

Science, 345
, 637-640, (2014).
6) S. Licht, H. Wu, X. Yu, Y. Wang, "Renewable Highest Capacity VB2/Air Energy Storage,"

Chemical Communication
, 2008, 3257-3259 (2008).
7) S. Licht, A. Douglas, R. Carter, M. Lefler, C. L. Pint, C. “Carbon Nanotubes Produced from Ambient Carbon Dioxide for
Environmentally Sustainable Lithium-Ion and Sodium-Ion Battery Anodes,”

ACS Central Science
, 2, 162-168 (2015).
8)J. Ren, S. Licht, “Tracking airborne CO2 mitigation and low cost transormation into valuable carbon nanotubes,”

Scientific Reports,
6, 27760-1-11 (2016).
9) S. Licht, B. Cui, J. Stuart, B. Wang, J. Lau, "Molten Air Batteries - A new, highest energy class of rechargeable batteries,"

Energy & Environmental Science
,6, 3646-3657, with 2 pages supplementary information (2013).
10) B. Cui, S. Licht,
"A Low Temperature Iron Molten Air Battery,"

Journal of Materials Chemistry A

,
2, 10577-10580, with 3 pages supplementary (2014).
11) S. Liu, X. Li, B. Cui, X. Liu , Y. Hao, Q. Guo, P. Xu, S. Licht,
"Critical advances for the iron molten air battery: A new lowest temperature, rechargeable,
ternary electrolyte domain,"

Journal of Materials Chemistry A,

3, 21039-21043, with 2 page Supplementary Info (2015).
12) B. Cui, X. Xiang, S. Liu, H. Xin, X. Liu, and Stuart Licht,

"A novel rechargeable zinc-air battery with molten salt electrolyte,"

Journal of

Power Sources,

342, 435-441.
(2017).
13) B. Cui, H. Xin, S. Liu, Xianjun Liu, Y. Hao, Q. Guo, and S. Licht,
"Improved cycle iron molten air battery performance using a robust fin air electrode,"

Journal of the Electrochemical Society
,
164, A88-A92 (2017).

14) Baochen Cui, Wei , Xiang, Shuzhi Liu, Hongyu Xin, Xianjun Liu, and Stuart Licht,
"A long cycle life, high coulombic iron molten air battery,"

Sustainable Energy & Fuels
, cover article, in press (2017).