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New high performance Janus electrode for rechargeable Na-S batteries

Researchers in China have designed a high-performance Janus electrode—i.e., containing both cathode and anode properties in the same body—for sodium-sulfur (Na-S) batteries by adopting a metal-organic framework (MOF) to incorporate single Yttrium atoms in a nitrogen-doped rhombododecahedron carbon host (Y SAs/NC).


The electrode features:

… favorable Janus properties of sodiophilicity and sulfiphilicity and thus presents highly desired electrochemical performance when used as a host of the sodium anode and the sulfur cathode of a Na–S full cell.

Impressively, the Na–S full cell is capable of delivering a high capacity of 822 mAh g–1 and shows superdurable cyclability (97.5% capacity retention over 1000 cycles at a high current density of 5 A g–1).

The proof-of-concept three-dimensional (3D) printed batteries and the Na–S pouch cell validate the potential practical applications of such Na–S batteries, shedding light on the development of promising Na–S full cells for future application in energy storage or power batteries.

—Zhang et al.

A paper on their work is published in the Journal of the American Chemical Society.


  • Erhuan Zhang, Xiang Hu, Lingzhe Meng, Min Qiu, Junxiang Chen, Yangjie Liu, Guiyu Liu, Zechao Zhuang, Xiaobo Zheng, Lirong Zheng, Yu Wang, Wei Tang, Zhouguang Lu, Jiatao Zhang, Zhenhai Wen, Dingsheng Wang, and Yadong Li (2022) “Single-Atom Yttrium Engineering Janus Electrode for Rechargeable Na–S Batteries” Journal of the American Chemical Society doi: 10.1021/jacs.2c07655



I just checked for a potential 'gotcha' in yttrium supply, but it seems hopeful:

' Yttrium is found in most rare-earth minerals,[9] it is found in some uranium ores, but is never found in the Earth's crust as a free element.[46] About 31 ppm of the Earth's crust is yttrium,[6] making it the 28th most abundant element, 400 times more common than silver.[47] Yttrium is found in soil in concentrations between 10 and 150 ppm (dry weight average of 23 ppm) and in sea water at 9 ppt.'

If I am checking something in any depth, I usually look for resources other than Wiki, but in this case it seems that at this early stage there are not sufficient grounds to be unduly concerned.

I fancy sodium sulfur much more than lithium in many applications for cost and availability reasons.


I joked about waiting for NaS batteries b/c they would be abundant and cheap...well...well!


Sodium batteries are already in production by CATL, so this represents an improvement to existing tech, not something brand new and theoretical.


NaS batteries are a very different beast from current Sodium-ion batteries.
NaS batteries have a very long commercial history as a "hot" battery where cathode and anode work in molten state. NGK were the biggest producer I think.
I don't know if this tech is room temperature or molten, but anything nano-tech should be taken with a pinch of salt. There is a thousand papers with good batteries which are impossible to mass produce given current tech.


Hi peskanov.

As you say, whether this is high or low temperature is unclear, but the low temperature versions can surely be fairly called NaS batteries too, as that is what the chemistry is.

Here is an article on CATL's sodium sulfur technology, where the big disadvantage is lower energy density than lithium.

In stationary storage, surely that is a 'so what?' issue, since the materials are so much cheaper?


I forget the link to the article on CATL's batteries.
Here it is:


unfortunately, the article you linked is paywalled. I can't find any reference about CATL battery using sulfur anyway.
My previous information about CATL battery is that they are using prussian blue or prussian white for the cathode, not sulfur. I don't think CATL battery is NaS; plus, NaS batteries are never called sodium-ion (maybe because they don't use intercalation?).

I don't have any problem with hot batteries for stationary uses; however, as I said before, stationary requires:
- Long life and robustness; ok, this thing seems to check.
- Cheap and scalable materials; nanotech MOF + yttrium does not sound good.

I took a peek at the paper; energy density is excellent. Round trip efficiency, I am not so sure (looking at the graphs).
I don't know, to me this battery goes to the "nice nanotech dreams" department. Someday we will be able to produce that kind of structures on the cheap, but not now and not soon.


Hi peskanov:

I got through to the site without going through a paywall, but then it may be something to do with cookie settings.

You are correct on the cathode of the CATL sodium battery.
It is not sulfur, and this is an instance of my lack of proper scientific background catching me out, as I simply assumed it to be sulfur - apologies.

Here is another, hopefully non paywalled, article on alternatives for sodium battery cathodes:

At 3.1 they remark:

' Furthermore, the most probable potential candidates for grid-scale energy storage requirements in the upcoming years would be O3-Na0.9Cu0.22Fe0.30Mn0.48O2, P2-Na2/3Fe1/2Mn1/2O2, NaxFe[Fe(CN)6], and Na4Fe3(PO4)2P2O7, as these materials are based on a facile synthetic method, are earth-abundant nontoxic elements, composed of high electronegative entities, and possess sufficient sodium-ion reservoirs.'

And at 3.2:

' Contemporary Amperex Technology Co., Ltd. (CATL) unveiled its first-generation sodium-ion battery utilizing Prussian white as the cathode material and demonstrated an energy density of up to 160 Wh kg–1 with their full cell for accomplishing the aim of carbon neutrality.'

Its above my pay grade to evaluate the suitability of the precise CATL formulation for stationary storage, but it seems to me from reading the above that earth abundant materials are likely to be suitable for the application without getting into molten NaS and its complications.

The bone I have to pick with lithium in the application in any really large scale is cost, as the materials are pretty pricey, and it seems we can do better, even excluding non battery storage where there are loads of alternatives.


the problem with lithium being expensive is real, but is part of bigger problem.
Check this:
- Lithium is more abundant than lead
- Every car has 15 kg (average) lead-acid battery which contains [b]9 kg of lead[/b]
-Every electric car has a big battery, but it only needs about [b]8 kg of lithium[/b]
Yet, lithium is much, much more expensive than lead.

Why? Because lithium was barely used before the ev explosive growth.
So, it would be better to use more common industrial elements with mature supply chains (btw yttrium not included in that list)...right? Yes, but it's not that easy.
This problem is going to be found in many more places; i.e right now there is a problem with synthetic graphite for batteries. Demand grows exponentially; raw material needed is common but the capacity of production of the specific refined material is lacking...therefore prices rise fast.

Bottlenecks are appearing everywhere, and many of them are unrelated to the scarcity of a given mineral.
This is is unavoidable for nearly every renewable technology growing fast; from magnets for wind turbines, to batteries or fuel cells.


I wrote quite a detailed response, which got eaten by the system here, but in essence the figures given in the table here seem good to me:

'3) Sodium-ion batteries, due to the chemical properties of their constituent elements, provide a low-cost, safe and, as we have already said, sustainable energy storage system. All these attributes make it, for example, a very suitable technology for the storage of renewable energies. The properties of lithium-ion batteries, for their part, are ideal for electric vehicles (largely thanks to their high energy density).'

Yttrium is suggested here for the fancy Na-S batteries, not the sort being currently produced and suggested for storage in the above.

There are other alternatives too, with lithium not really being great where high energy density is not required.

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