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Stanford team develops sodium-ion battery with performance equivalent to Li-ion, but at much lower cost

10 October 2017

Stanford researchers have developed a sodium-ion battery (SIB) that can store the same amount of energy as a state-of-the-art lithium ion, at substantially lower cost. As reported in a paper in Nature Energy, the Stanford team achieved four-sodium storage in a Na2C6O6 electrode with a reversible capacity of 484 mAh g−1, an energy density of 726 Wh kg−1cathode, an energy efficiency above 87% and a good cycle retention.

Chemical engineer Zhenan Bao and her faculty collaborators, materials scientists Yi Cui and William Chueh, aren’t the first researchers to design a sodium-ion battery; however, they believe their approach has the price and performance characteristics to create a sodium-ion battery costing less than 80$% of a lithium ion battery with the same storage capacity.

The rise of renewable solar and wind power is demanding sustainable storage technologies using components that are inexpensive, Earth-abundant and environmental friendly. There have been exciting advances in the performance of SIBs utilizing layered transition-metal oxides and polyanions, which suggest that the sodium compounds can be promising compared with their lithium analogues. The layered metal oxides offer high energy densities but are limited by cycling stability and air sensitivity, whereas polyanions show rather stable cycle life but only deliver a moderate energy density. Thus, further research is required to find better sodium host materials. In addition, material sustainability is also a critical factor when considering the total economic and environmental benefits for grid-scale energy storage applications.

Organic compounds that can be obtained from natural biomass with minimum energy consumption are an attractive low-cost and sustainable choice for battery electrode materials, provided a high energy density and long cycling stability can be obtained. … Later work turned to disodium rhodizonate (Na2C6O6), and demonstrated excellent cycle stability in SIB. Although it seemed intuitive to expect a similar four-electron redox reaction in Na2C6O6, previous studies have experienced challenges in repeatedly utilizing four electrons. Rather, there was a substantial capacity loss after the first cycle, and the following reversible capacity was much lower than its theoretical capacity of 501 mAh g−1. Despite its crucial importance, the origin of this discrepancy remains unknown.

Here, we reveal the origin of the limited electrochemical performance of Na2C6O6 and provide an effective path to achieve reversible four-sodium storage.

—Lee et al.

In the Stanford battery, a sodium ion binds to a compound known as myo-inositol—a household product found in baby formula and derived from rice bran or from a liquid byproduct of the process used to mill corn. Crucial to the idea of lowering the cost of battery materials, myo-inositol is an abundant organic compound familiar to industry.

The sodium salt makes up the cathode; the anode is made up of phosphorous. For this prototype, postdoctoral scholar Min Ah Lee and the Stanford team improved how sodium and myo-inositol enable the electron flow, significantly boosting the performance of this sodium-ion battery over previous attempts.

They found that the irreversible phase transformation of Na2C6O6 during cycling is the origin of the deteriorating redox activity of Na2C6O6. They identified active-particle size and electrolyte conditions as key factors to decrease the activation barrier of the phase transformation during desodiation.

The researchers focused mainly on the favorable cost-performance comparisons between their sodium-ion battery and lithium. In the future they’ll have to look at volumetric energy density—how big must a sodium ion battery be to store the same energy as a lithium ion system.

In addition, the team optimized their battery’s charge-recharge cycle. To better understand the atomic-level forces at play during this process, postdoctoral scholar Jihyun Hong and graduate student Kipil Lim worked with Chueh and Michael Toney, a scientist with the SLAC National Accelerator Laboratory. They studied precisely how the sodium ions attach and detach from the cathode, an insight that helped improve their overall battery design and performance.

The Stanford researchers believe their Nature Energy paper demonstrates that sodium-based batteries can be cost-effective alternatives to lithium-based batteries. Having already optimized the cathode and charging cycle, the researchers plan to focus next on tweaking the anode of their sodium-ion battery.

This is already a good design, but we are confident that it can be improved by further optimizing the phosphorus anode.

—Yi Cui

Other members of the team included Stanford researchers Jeffrey Lopez, Yongming Sun and Dawei Feng. The work was funded by the U.S. Department of Energy’s Advanced Battery Materials Research (BMR) Program. X-ray measurements were carried out at the Stanford Synchrotron Radiation Laboratory (SSRL), a national user facility operated by Stanford University on behalf of the U.S. Department of Energy, Office of Basic Energy Sciences.

Resources

  • Minah Lee, Jihyun Hong, Jeffrey Lopez, Yongming Sun, Dawei Feng, Kipil Lim, William C. Chueh, Michael F. Toney, Yi Cui & Zhenan Bao (2017) “High-performance sodium–organic battery by realizing four-sodium storage in disodium rhodizonate” Nature Energy doi: 10.1038/s41560-017-0014-y

October 10, 2017 in Batteries, Smart Grid | Permalink | Comments (10)

Comments

¿Donde están los datos totales de la celda no el Catodo?. Sin esas cifras el anuncio no vale para nada.......

This could be your overnight storage battery.
It might be too heavy, or too bulky for vehicular use, but fine for stationary storage.
It would be a huge boon to the whole renewables industry if it panned out. Places could go almost off grid if you had this.

[IMO, you'll never go fully off grid using just solar and batteries, as you will get storms and monsoons and other weather events that last several days, and for those, you either use a diesel generator, or go lights out. When you consider that many isolated places are already lights out, this would pan out.
[ In fact, they could go "everything heavy out, lights and phones still on" ]
The problem would be fridges containing food or vaccines, you could do without sewing machines and Ac for a few days, but you would need to keep the medicine cool.

Batteries are OK for NO-BREAK power systems but another power source (or many more batteries) is essential for longer or extended periods.

An added small FC, (with an H2 supply), enough for a few rainy-cloudy days and automatic non essential loads cut off would be required. It is doable between $0.20 and $0.30/kWh in homes with large (southward) roofs in sunny places.

In extreme weather conditions, solar power with battery backup could be more reliable than the grid, particularly if a fully charged EV was in the driveway. Furthermore, If the weather event is localized the EV may be able to recharge repeatedly at remote sites that still have power.

For widespread events, such as occurred in the Florida Keys, an EV would only represent a possible one-shot source of battery power.

Most existing power grids are not built to resist major hurricanes or icing rain. Many local distribution lines cannot even resist Cat I storms and are subjected to fallen trees and broken poles and quick failures.

High voltage power lines, in or close to adverse weather areas, will have to be strengthen to better resist adverse weather. Local distribution lines and communication cables may/will have to be burried as already done in our area and in many EU countries.

Fresh water plants should be better protected against flooding and be equipped with back-up reliable power plants and enough fuel for 30+ days.

If not done, residants of islands, States and countries in or adjacent to tropical storms areas will face more more suffering and miseries.

Under ground utilities.

Underground utilities will take years, if not decades to put in place.
if you are worried about storms, I would suggest batteries and a diesel generator and leave the AC off.
@harvey: A fuel cell might be cleaner, but you won't need to run the generator very often, so it won't pollute very much on an annual basis, and it will be cheaper and diesel is much easier to store than H2.

They could have started with under ground utilities decades ago, but they would rather put back up power poles year after year.

Underground cables were installed many decades ago in our area and we pay the same rates as people with low resistant electric poles.

The initial cost per kWh/year is very low. People living in hurricane regions would NO LONGER object to pay a bit more for resistant electrical networks.

Current e-networks in Porto Rico and many Golf States are shameful. Hospitals, watter treatment plants, schools, residences and prisons built in low lands is as shameful?

Southern USA will have to wake up or the rest of the country will have to continue to pay dearly.

This is a good design for a Sodium Ion battery. My only question is why the Phosphorus anode? According to Yi Cui, "Phosphorus is an attractive negative electrode material for sodium ion batteries due to its high theoretical specific capacity ... it suffers poor conductivity .., slow reaction dynamics, and large volume expansion (440%) during the sodiation process, leading to rapid capacity decay" (reference: https://web.stanford.edu/group/cui_group/papers/JieS_Cui_ESM_2016.pdf).
Why not use John Goodenough's Sodium Metal anode which appears to have solved that anode's dendrite problem using a solid electrolyte? (reference: "Alternative strategy for a safe rechargeable battery", http://pubs.rsc.org/-/content/articlehtml/2016/ee/c6ee02888h).

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