Grid Think

I have written about the economics before, $4/lb or $9/kg of Chinese Vanadium Pentoxide makes $70/kWh in just the electrolyte cost of the Vanadium Flow batteries, this cost excludes converting the ore into battery grade electrolyte, tanks, pumps, pipes and cell stack (which adds up  quickly by the way), the total cost of the system can sit well above $200/kWh depending on the specs of the battery. Now if you want an LFP battery, its landed cost would be around $120/kWh. That's a 40% discount !! So the obvious question arises, who buys such an expensive battery ? And how does it make any financial sense to buy a VFB ? If you consider the upfront cost of VFBs they can never be competitive- You can say that LFP degrades and VFB doesn't, so over a long period of time, VFB would be cheaper, but VFB takes a lot more space, and that cost has to be accounted for, I have run some financial models but VFBs can never be competitive with LFPs, let alone much cheaper Sodium Ion batteries ab...

So I have decided to embrace the fact that Fe-Cr batteries operate at a fundamentally higher temperature. But now you'll say it makes no sense to heat the battery, the costs alone would bankrupt me.  Let's take a sample system of 1 MW / 10 MWh,  If we assume a conservative energy density of 10 Wh/L, Volume of electrolyte (L) = Total energy required  / Energy density  Volume =  10,000,000Wh / 10 Wh/L  =1,000,000 L  We would need 1 million liters of electrolyte and calculate the mass of water as by keeping density as 1 kg/L.  mass (kg) = volume  x density of water  m = 1,000,000 L x 1 kg/L = 1,000,000 kg  If I take the conservative specific heat of water as 4,187 J/kg·K, s tart with an ambient temperature of 20°C and keep my ΔT as 20°C,  Q (heat energy) = m x c x ΔT   m = mass of water = 1,000,000 kg , c = specific heat capacity of water = 4,187 J/(kg·K)  ΔT = temperature change = 40°C - 20°C = 20 K   Q =...

You know I have been wrong before, but never so pleasantly surprised. I spent the last two months trying to copy VRFB........ well, not exactly. I wanted to make an Iron-Chromium Redox Flow Battery that was just as good as VRFB. That means its power density, efficiencies and performance should match closely with VRFB.  But as I have stated many times earlier, Fe-Cr batteries have a fundamental flaw, they can't operate at room temperature, which is the fundamental reason why they have not been commercialized yet. In my previous post I wrote about a paper that I had recently found, it added salt to the battery in order to enable it to operate  at room temperature. Let's understand how  The paper used salt to increase the kinetics of chromium at room temperature. This happened because the lithium (or in my case sodium) chloride increased the concentration of chloride ions in the electrolyte solution. This causes excessive Cl⁻ ions in the electrolyte solution and increased c...

In my previous posts I have written a lot about the trident of problems with Iron-Chromium Redox Flow Battery, which are -  Hydrogen Evolution Reaction Slow Chromium Kinetics High operating temperature for the battery Now if you ask an AI (Gemini in my case), one of the first answers it will give would be Bismuth as master solution to all 3. It stops Hydrogen evolution and makes chromium react faster, hence solving all the problems of the battery. It does that by  acting as a catalyst. It forces the Cr3+ to accept electron quickly and react faster, and it has a more positive electrode potential (+0.32 V), as compared to chromium (-0.41 V), this stops water from splitting into hydrogen. Source But first you need to understand how Bismuth is incorporated in the battery - The Mechanisms- In order to use bismuth or any other catalyst in a flow battery, you have 2 choices - Electrodeposition-   Dissolve bismuth chloride in the liquid electrolyte and when you apply voltage...

Nafion and FumaSep, both membranes are pretty expensive for me, and if they are expensive for me I don't think they would be any cheaper for any Flow Battery manufacturer. Because its basic economics, if your raw materials are expensive your end product can't be cheap. So most flow battery manufacturers don't really bother with inventing new membranes, they use a material called DARAMIC separator, it is made up of Polypropylene (PP) or Polyethylene (PE) sheets with micro level holes in them, nothing new, its a 50 year old separator material which is used to separate positive and negative side. Daramic is used in literally all batteries, you name it, Lithium Ion, Sodium Ion, Lead Acid , All- Iron Hybrid Batteries and yes even Vanadium Redox Flow Batteries.  Source There has been substantial amount of research on cheap membranes, but most of them last only a few weeks and the membranes that actually last.... well they are Nafion and Fumasep. But Daramic works in a fundamental...

Full disclosure, I haven't made the best flow battery cell stack. If you have been reading my blog, I haven't even designed it myself. I have been replicating the cell stack from a Youtuber named CAYREX , every battery enthusiast should check his channel out.  But I have been lazy, instead of reading books, research papers and patents on stack design and designing my own cell stack, I just took the STL files from Cayrex's Patreon page and got them 3d printed, but after months of battery testing and troubleshooting with someone else's stack. I'll be breaking down the difference between Industrial grade stacks and a DIY stack. The images I will show will be mainly of CAYREX's stack, but this is applicable for all DIY and lab scale stacks Problem 1- Screws This is a photo of flow battery cell stack from the internet - Image 1-   Source  This is a good stack but, its problem is that the screws are inside the stack housing. These will corrode very badly the moment th...

I'll be honest, I have a tendency to nerd out about stuff and not really take action on it, so every once in a while I push myself to BUILD the battery, because AI can "brainstorm" all day, but can't build a battery So after reading some research papers on Iron-Chromium battery, I decided to build one, but this time I wanted to get some visual result, something a 5 year old kid can recognize, I had to light up an LED, but a single of Iron-Chromium battery has voltage of 1 Volt. That doesn't do anything. So I had to build another cell stack to get 2 V, this easily lights up a Red LED  . Making the Stack So ordered the 3D printed parts from online shop, I already had Iron chloride from my all iron build, I ordered Chromium Chloride (very cheap, very easily available, order online). If you want to know how to build it you can see my previous post . Since I already had a leak proof cell, making another one was not really a problem I just used some RO fittings and join...

If Iron Chromium Redox Flow Battery is so cheap, abundant, simple and elegant...... Why isn't it everywhere ? Why was Vanadium even needed in the first place ? Why hasn't anyone commercialized it yet ? Well..... because it has its own set of problems. Physics and economics aren't really best friends, the more money you spend the better battery you get, the cheaper you get, your efficiency takes a plunge. And trust me you DON'T want a shitty battery. The way I see it for flow batteries- Vanadium is expensive but simple and has good efficiency Iron Chromium is cheaper than Vanadium, but more expensive than Iron, so it has Hydrogen problem of Iron but manufacturing simplicity and efficiency of Vanadium. Iron is dirt cheap, but I would personally not buy it, I don't want a battery that wastes half its energy, because you have to pay for every unit you put in. This is my take on viable redox flow battery chemistries. Don't get me wrong, there are many newer more amaz...

Energy Storage Systems Technology (ESS Tech Inc), the star child of flow battery industry, one of the few flow battery companies to ever go public, a technology with raw materials so cheap that you could buy them for pennies. This is the company I looked up to for 3 months, the ingenuity in their technology. Of course, a battery of iron is the way to go, its an economic masterstroke. Source But I was missing something, if it was so easy to build, why wasn't everyone doing this. All Iron redox flow battery should be easy, if any Indian or Chinese manufacturer knew about this technology, they would reverse engineer it in 1 year.  But I was wrong, not only because they hold a LOT of patents (103 granted, 214 filed), but also because physics doesn't give free lunch. So here are the roadblocks I ran headfirst into, while trying to copy ESS. 1. The Stack  As I mentioned in the last post , charging an Iron Redox Flow Battery is like electroplating, it requires slow charging, which me...

Iron and Vanadium based electrolytes can both be used Redox flow batteries, both use tanks, pumps and cell stack, but they don't operate the same way. While Vanadium Redox Flow Batteries stay completely liquid in their operation, All Iron Hybrid Batteries don't. And the name itself tells you why-  Hybrid. When you charge an All Iron battery, its positive side converts Fe2+ to Fe3+, and stays liquid, but the negative side converts Fe2+ to Fe0, or solid iron.  So why is solid iron a problem ? Well because - 1.The electrode that we have used i.e. graphitic carbon felt, is a conductive sponge, it is designed to absorb liquid and transfer electrical energy to it, it instantly clogs when solid iron is deposited on it. 2. Solid iron is not soft, nor does it grow evenly, it grows in the shape of needles or dendrites (if you have ever seen iron filings, that's solid iron). Iron dendrites 3. Deposition of solid iron is also called electroplating, and current density in electroplating...

When I left the Iron Redox Flow Battery overnight connected to the AA battery, and switched on the pumps again in the morning, I immediately noticed brown liquid flowing through the pipe into the tank, so I asked AI what happened (novice here too !!😇), then I had to understand how exactly a battery works. So buck up, now we are going into depths of battery science, but first the basic- Current is how many electrons can you push in the circuit per second, voltage is how hard you can push them, current density is how many electrons can pass through battery electrode per unit area per second. The higher the current density; faster the battery charges, lower the current density; slower the battery charges. But remember, per unit area, so the total amount of current flowing in the battery is dependent on area of the electrode also. A good battery crams as many electrons possible as quickly as possible in a unit area of the electrode. For instance, when you connect a fast/turbo charger to y...

So, when looking for a cheaper alternative to Vanadium batteries, I stumbled upon all iron chemistry,  the absolute cheapest battery chemistry possible, using only iron, the most mined element from Earth's crust. The metal so cheap that its literally the basis of human civilization. No need to heat the battery, no need to check supply chains, Iron is so abundant that you can find it wherever humans are. I was convinced, Gemini gave me the broke college kid solution. So I ordered Iron chloride from the internet, you know how much lab grade 500g highest purity cost me ? Rs 800 ($8), that's pennies as compared to Vanadium. So before I give you step by step procedure of building you own Iron Redox Flow Battery we need to understand how it works. Working of Iron Redox Flow Battery Similar to Vanadium, Iron redox flow battery has iron on both sides, on both sides it is in Fe2+ state, when it charges on the positive side it converts Fe2+ to Fe3+ (loses 1 electron) and on the negative ...

 I'll be honest, I didn't dream of Iron Chromium Redox flow battery in my dreams, nor did I have any secret information from NASA. I did what any other 22 year old would, ask Gemini about it. If you ask Gemini or ChatGPT about VRFBs, there are high chances that it will suggest alternate chemistries also. Now that can be a good thing or a bad thing. If you know a little bit electrochemistry, it would spit out a very obvious answer. If you don't, you'll go down the same rabbit hole I did. AI doesn't know your intentions. So it acts as the most efficient information summarizer, and that's great, if you just want information, not if you want action. So one of the first alternatives to VRFBs Gemini suggested was Iron - Chromium, and it made a lot of sense because Iron and Chromium are commodity metals, Iron is literally the most mined metal on earth and chromium comes third [ source ]. Their commodity prices are - Iron - $110 per ton   (at the time of writing) Chromi...

 I love AI, its the perfect expert and assistant, I always wished for. I am very sure so do most of its users, yes there are some problems with it. But I am sure world's best engineers sitting in these companies will solve them. But here's a problem 99% of coders cannot possibly solve in their cubicles, and it decides how your favorite AI behaves, power supply. Let's talk about Claude, because I am using Claude nowadays, but I have seen a very similar pattern in Google's Gemini Pro (student version) and ChatGPT. So feel free to generalize this issue Free User Experience If you have asked any AI model to perform complex tasks for you, or make complex decisions, most AI models take time, somewhere between a few seconds to sometimes Claude taking minutes to draft documents. Not a dealbreaker, but I wish it was faster, since I am so used to speed now. Also as a non-premium user of any of the AI models, I have also seen that they hit a limit. In many cases for premium users ...

After reading the Vanadium post, I am sure its pretty clear that VRFBs are expensive but they are one of the oldest, most stable, most deployed and proven redox flow battery chemistry yet. So, I feel its worth giving Vanadium another chance before dismissing it fully. Vanadium Supply Chain As of 2026, global Vanadium production is 100,000 metric tons, that may sound like a lot, but its tiny, to put that in perspective, we produce 3x more Lithium and we still need to discover and open new lithium mines, and Lithium supply chains are considered to be volatile.  Since we are talking about supply chain, its obvious to see when you buy Lithium or Vanadium ores, where exactly are they being dug up. Lithium producing countries- Source Vanadium producing countries - Source I'll be honest even I am a little surprised, I imagined Lithium to be produced in China, and its an obvious assumption, if the biggest lithium ion battery makers are Chinese, it would be obvious to think that its produce...

Search flow batteries anywhere on the internet, you'll find Vanadium's monopoly, ask any AI model about flow batteries and they'll assume vanadium and give you all the information. That's because Vanadium Redox Flow Batteries (or VRFBs in short) are already being commercialized, or at least they're trying their best.  I'll try to explain why, but before i move further, i forgot to explain the redox part in the last 2 posts. All Batteries are Redox Batteries- Batteries have 3 basic parts, positive side (cathode), negative side (anode) and a membrane or separator. So, when you connect a charger to your phone, the charger takes electrons from positive and gives it to the negative side, but if the positive and negative mix together they will neutralize each other, so they need to be separated by separator (or membrane). The word "redox" is made of two words : Reduction- gaining of electrons (by the negative side) Oxidation - loss of electrons (by the posit...