• Fayaz Ahmed

Most Promising Battery Storage Technologies

Updated: Mar 15, 2021

(Photo Courtesy: Battery Storage Technology: Opportunities and Uses Course by Future Learn)

Large scale affordable energy storage is fundamental to the sustainable energy future. Out of all energy storage technologies, I foresee battery storage technologies playing critical role in the transformation of our energy system.

Battery storage technologies have seen tremendous growth in the last decade. In 2010, batteries could power only our phones, computers and other portable electronics. But by the end of the decade, they have started powering our cars, houses, and power grids too.

To be honest, it’s hard to keep up with advancements in the battery storage world. Since the 1990s, more than 300,000 battery-related patents have been filed (more than 30,000 in 2017 alone).

Nevertheless, the battery storage technologies I am very excited about are following:

Lithium-ion Batteries

When talking about Li-ion batteries, it’s important to understand that Li-ion is not a single battery type rather it’s a family of batteries with different chemistry variations mostly on the cathode side while graphite being the most common anode.

Six main chemistry variations falling under the family of Li-ion batteries:

  • Lithium Cobalt Oxide(LiCoO2) — LCO

  • Lithium Manganese Oxide (LiMn2O4) — LMO

  • Lithium Nickel Manganese Cobalt Oxide (LiNiMnCoO2) — NMC

  • Lithium Iron Phosphate(LiFePO4) — LFP

  • Lithium Nickel Cobalt Aluminum Oxide (LiNiCoAlO2) — NCA

  • Lithium Titanate (Li2TiO3) — LTO

How do they work?

In Li-ion batteries, lithium ions are stored in active materials acting as stable host structures (known as cathode and anode) during charge and discharge.

Traditionally graphite has been used as an anode material but currently researchers and battery manufacturers are seriously working on replacing graphite anodes with silicon and lithium metal because of their extremely high theoretical specific capacities (such as 4000 mAh g−1 for silicon, and 3860 mA h g−1 for Lithium (Li) metal) compared to that of 372 mAh g−1 of graphite.

On the cathodes side, overall trend is to move towards a high nickel cathode design and completely get rid of cobalt without sacrificing capacity or cycle life.

Although there are lots of technical challenges before these changes can be implemented in the designs of anode and cathode materials but it looks like we are on the right path.

What are its advantages?

  • Boasting highest energy densities among all the state-of-the-art storage technologies.

  • Large choice of cell designs and battery chemistries

  • Experiencing very low self-discharge rates

  • Better cycling performances, typically thousands of charging/discharging cycles.

  • Long lifetime

Future Prospects

Lithium-ion batteries are anticipated to have a high rate of deployment in the coming decades. Ideal applications of Lithium-ion batteries would be energy storage systems for renewables and transportation.

Lithium-Sulfur Battery

How does it work?

Lithium-sulfur (Li-S) batteries design use sulfur in the positive electrode and metallic lithium as the negative electrode.

The key difference between Lithium-sulfur (Li-S) batteries and Li-ion batteries. Unlike Li-ion batteries, which need host structures for storing lithium ions during charge and discharge. Lithium-sulfur (Li-S) batteries need no host structures. While discharging, the lithium anode is consumed and sulfur transformed into a variety of chemical compounds; during charging, the reverse process takes place.

What are its advantages?

  • Battery design with very light active materials

  • Four times greater theoretical energy density than that of Li-ion batteries

  • Promising candidate for aviation and space industries

Future Prospects

Saft, a battery manufacturer, claims that major technical challenges for Lithium-sulfur (Li-S) battery technology have already been overcome and Lithium-sulfur (Li-S) battery technology quickly heading towards full scale prototypes. But if we are talking about applications requiring long battery life, we are at least 5 years away from making it happen.

Solid-State Battery

How does it work?

Before talking about Solid-state batteries. It’s important to talk about an electrolyte. In modern Li-ion batteries, Li-ions move from one electrode to another across the liquid electrolyte (also called ionic conductivity). Solid-state batteries replaces liquid electrolyte with some solid compounds (such as polymers and inorganic compounds) without losing the ion migration ability.

Many world known researchers are working on finding and testing new solid electrolyte materials with high ionic conductivity just like liquid electrolytes.

What are its advantages?

  • Improved safety due to non-flammable solid electrolyte materials

  • Opening the possibility of allowing voltage high-capacity materials in the design

  • Overall simplified mechanics and better thermal performance

Future Prospects

According to Cockrell School of Engineering at The University of Texas at Austin website, A team of engineers led by 94-year-old John Goodenough, professor in the Cockrell School of Engineering at The University of Texas at Austin and co-inventor of the lithium-ion battery, has developed the first all-solid-state battery cells that could lead to safer, faster-charging, longer-lasting rechargeable batteries for handheld mobile devices, electric cars and stationary energy storage.

Solid-state batteries with graphite-based anodes, and metallic lithium anode are likely to enter the market in the future as technological progress continues.

Sodium-ion battery

How does it work?

The sodium-ion battery works exactly similar to that of Li-ion batteries. The key difference between sodium-ion battery and Li-ion batteries is that In sodium-ion battery, instead of lithium ions, sodium ions (Na+) ions are stored in active materials acting as stable host structures (known as cathode and anode) during charge and discharge.

There is a need to research and find more innovative host structure materials that can store the larger sodium ion in appreciable quantities.

What are its advantages?

  • Sodium is a cheaper alternative to lithium

  • Sodium is the sixth most common element on the planet

  • Sodium-ion batteries can significantly lower battery technology cost

Future Prospects

Nevertheless, commercialising sodium-ion batteries is expected to begin for smartphones, cars and more in the next five to 10 years.

Lithium-air battery

How does it work?

The idea of Lithium-air battery occurred accidently to chemist K M Abraham while testing a battery cell having a small leak in his laboratory in 1995, which provided the cell with far higher energy content than expected. Rather than try to fix the leak, he investigated and discovered the first rechargeable lithium-air (Li-air) battery.

Lithium-air battery comprises of a metal electrode which is lithium in this case, electrolyte which could be either aqueous or non-aqueous, and a cathode structure for the reduction of oxygen. Lithium-air battery cell design uses oxidation of lithium at the anode and reduction of oxygen at the cathode to induce a current flow.

What are its advantages?

  • Lithium-air battery technology can yield five times more energy density than commercial lithium-ion battery technology

  • Significant volume and the weight reductions of the battery system compared to Li-ion systems

Future Prospects

At the moment it's quite challenging to recharge a lithium-air battery more than a few times due to the oxidation of the lithium anode and production of undesirable by-products on the cathode that result from lithium ions combining with carbon dioxide and water vapor in the air. Therefore, we are far from witnessing lithium-air battery technology being used for applications requiring long battery life.

Vanadium Redox Flow Batte

Lithium-ion battery technology may seem to be dominating low volume niche such as personal devices and electric vehicles market, but when it comes to the utility-scale commercial battery market, still there is not a single clear winner. One of the latest technology to emerge for utility-scale commercial battery market is called vanadium redox battery.

How does it work?

Flow batteries consist of two tanks of liquid commonly called electrolytes or working fluids. When pumped into a chemical reactor, chemical energy of working fluids is converted into electrical energy through reversible oxidation and reductions reactions back and forth during charging and discharging.

What are its advantages?

  • Discharge 100% of the stored energy

  • Do not degrade for more than 20 years

  • The Earth’s crust has much more vanadium than lithium

  • Offer almost unlimited energy capacity simply by using larger electrolyte storage tanks

  • Decoupling of energy rating and power rating is an important feature of flow battery systems.

Future Prospects

Vanadium flow batteries can be quite large and best suited to industrial and utility scale applications. They’re just safer, more scalable, longer-lasting.

Most commonly used chemistries for redox flow batteries are based on materials like vanadium, zinc, and iron. And although vanadium and zinc-based flow batteries are close to commercialization, but high cost of the vanadium and relatively low power and energy densities are still some key challenges standing in the way of further commercial and industrial application of Redox Flow batteries.

Finally It’s true that there is no one particular battery technology that could satisfy the energy needs of future. While the exact type of battery that will win out is unknown, what’s certain is that batteries will play an even larger role in powering our lives going forward.








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