I was/am not particularly familiar with this technology, and as such, I picked up a few review articles on the topic and quickly scanned them.
Mostly I focused on this one, from a Canadian Institution, not because of its title, but because it has a nice easy to read quick overview of the technology,
A review of all‐vanadium redox flow battery durability: Degradation mechanisms and mitigation strategies (Xiao‐Zi Yuan, Chaojie Song, Alison Platt, Nana Zhao, Haijiang Wang, Hui Li, Khalid Fatih Darren Jang, Int J Energy Res. 2019;43:6599–6638.
...and this one...
A high power density and long cycle life vanadium redox flow battery (H.R. Jiang, J. Sun, L. Wei, M.C. Wu, W. Shyy, T.S. Zhao Energy Storage Materials 24 (2020) 529–540 Volume 24, January 2020, Pages 529-540)
Although I appreciate you drawing my attention to them, the topic does nothing to mitigate my general feeling about batteries in general, which are generally supposed to offer hope that the grotesque failure of so called "renewable energy" to address climate change can be mitigated by band-aid after band-aid after band-aid applied with huge dollops of wishful thinking.
With respect to so called renewable energy, a battery does two things: (1) It raises the already unacceptably low energy to mass ratio of this pernicious technology on which we have bet the planetary atmosphere. (2) It rejects heat energy (entropy) to the atmosphere, thus wasting energy.
One doesn't need to even read the full text of the second paper cited, to get to the second point. It's in the abstract:
At the current densities of 200, 400 and 600 mA cm−2, the battery achieves the energy efficiencies of 91.98%, 86.45% and 80.83%, as well as the electrolyte utilizations of 87.97%, 85.21% and 76.98%, respectively. Even at an ultra-high current density of 1000 mA cm−2, the battery is still able to maintain an energy efficiency of as high as 70.40%.
These energy losses to sustain an already trivial form of energy are treated as a victory. They are not, because electricity is not primary energy, but is rather a thermodynamically degraded form of energy by its very nature. The batteries simply add another layer (two layers actually) to the thermodynamic losses associated with electricity.
(I am currently working on writing an article for this space on the electrochemical reduction of carbon dioxide to give multicarbon molecules during which I may discuss an alternate approach designed to store energy
by capture of the energy losses to thermodyanmics inherent in all heat engines, i.e. raising their efficiency. I may get it up today, depending on the flow of time and responsibilities.)
Now, for sure, there are
local applicability to batteries. While I object vociferously to exajoule scale battery storage, a battery or fuel cell device to provide immediate back up for systems that require continuous operation, cell phone towers, lighting in large buildings during power outages, etc. I am far less sanguine about devices such as electric cars, which to my thinking, represent an environmentally unacceptable abomination.
Thanks for your question though. I very much appreciate questions that make me look into something about which I know nothing or very little.
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