Vanadium vs. Lithium

6 Advantages of Vanadium Redox Batteries Over Lithium

 

1. Lifetime

Unlike a lithium battery, a vanadium redox battery has an essentially infinite lifetime.   The source of this advantage is the inherent nature of the battery chemistry; the electrochemical reactions within a vanadium redox battery occur at the surface of the graphite electrodes, and both oxidized and reduced species remain dissolved in the electrolyte, as such no forces are exerted on the graphite electrode.  In the case of a lithium ion battery, the lithium cation gets inserted between planes of graphite (an intercalation compound) creating stresses on the electrode as charge/discharge cycles occur.

The limiting factors affecting the lifetime of a vanadium redox battery are bulk components, such as plastic tanks that can last more than twenty years.  In the case of a lithium ion battery, the capacity can drop by 50% within only 1500 cycles, requiring full replacement.  For grid-based battery energy storage, vanadium redox batteries are far more useful than lithium.

2. Scalability

Vanadium redox batteries have independent power and energy capacities; as such to add additional lifetime one can simply increase the size of the vanadium electrolyte storage tanks.  They are capable of being mass produced using modular parts where to increase the power or energy capacity of the system a component can be switched out with one of targeted properties that is mass produced for a modular system.  These economies of scale with modular parts result in lower manufacturing costs and simple production results in being able to put together a vanadium redox battery factory for far cheaper than a lithium ion battery factory.

The low margins and difficult manufacturing of lithium ion batteries compared to vanadium means that recently lithium ion manufacturer A123 systems declared bankruptcy, despite the current trend towards electric vehicles. In regards to the lithium ion battery manufacturing business, Sam Jaffe, senior research analyst at Navigant Research had this to say: “The lithium ion battery manufacturing space is not for the weak of heart… The electric vehicle market is growing slowly and the battery manufacturers are engaged in a Darwinian fight for survival.”

The modular nature and easy scalability of the vanadium redox battery compared to lithium is another factor contributing to the superior nature of vanadium for energy storage.

 

3. Environmental Impact

Lithium ion batteries are not currently recycled.  The active ingredient lithium salts only make up a small percentage of the battery weight, and the lithium cost is only 3% of the entire battery cost.  Even if lithim batteries were recycled for their lithium content, the recovered lithium would be 5 times the price as freshly-mined lithium; the economics prevent adoption.  As a result, lithium ion batteries are discarded as waste.

In contrast, the vanadium content of a vanadium redox battery is easily recycled at the end of  its life and used in new flow battery systems.  Vanadium also has the advantage of being recovered from industrial waste products such as fly ash or mine tailings.  The process of vanadium recovery from these sources actually cleans up the environment.

Another reason that when vanadium redox batteries vs. lithium ion are compared, VRBs come out on top.

4. Safety

Lithium batteries have the potential of thermal runaway producing fires or even explosions.  A vanadium redox battery has zero chance of this.  Indeed, the fact that the vanadium is dissolved in a water based electrolyte means that it is completely non-flammable and should a fire in the vicinity of a vanadium redox battery breach the storage tanks, could put out the fire.

5. Cost

Lithium ion batteries currently cost around $1750/kWh, however once Tesla’s Gigafactory comes online by 2020 this should reduce to $500/kWh retail.  This cost included all supporting technology as well such as associated electronics and installation.  In contrast, vanadium redox batteries are already capable of being sold for $500/kWh, and it is anticipated that this will come down to $150/kWh by 2020.

Unlike a lithium ion battery, the cost for a vanadium redox battery system actually decreases as it gets larger. In a lithium ion battery, if you want to double the capacity, you double the cost; with vanadium you just double the size of the tank, a small cost relative to the entire system.

6. Convenience

While the ability to charge a battery by switching the electrolyte is unnecessary when charging slowly such as in a grid-leveling application, a major limitation of electric vehicles is the slow charging times compared to the quick refueling of an internal combustion engine automobile.  For example, a Tesla when charging from a standard 120 V, 12 A outlet will only get3 miles of range per hour of charging. In comparison, one can easily see the advantages of a flow battery with easily swappable electrolyte; a ‘vanadium station’ could swap the electrolyte in a time comparable to refueling an internal combustion vehicle.

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