양극 프리 나트륨 고체 전지는 ‘리튬 삼각지대’ 의존도를 줄일 수 있다

배터리를 만드는 다양한 방법

Battery makers are constantly innovating in a race to make the best technology.  In recent years, this has been driven by the incentive to capture the ever-growing EV market and the nascent but even quicker-growing utility-scale battery market.

Once built on lithium-ion technology, batteries are looking beyond this design to solve the issues of Li-ion: too expensive, using rare metals, fire risks, etc.

Source: Research Gate

그러한 대안 중 하나는 나트륨 이온 배터리로, 리튬 대신 나트륨을 사용하지만 에너지 밀도가 낮다는 단점이 있습니다.

또 다른 대안은 고체 전지입니다. 전해질이 필요 없게 함으로써 더 높은 밀도를 가질 수 있어 동일한 전기차 성능을 위해 필요한 전해질 양이 줄어듭니다. 고체 전지는 충전 속도도 훨씬 빠를 것으로 기대됩니다.

좀 더 대담한 접근 방식은 화학 물질만 바꾸는 것이 아니라 배터리 자체의 구조를 바꾸는 것입니다. 특히, 양극 프리 배터리는 배터리의 한 부분을 완전히 제거합니다.

Researchers are now looking to combine these approaches together, notably with the recent publication of a design for the world’s first anode-free sodium solid-state battery.

양극 프리 나트륨 고체 전지

게시일 in Nature Energy under the title ”Design principles for enabling an anode-free sodium all-solid-state battery“, the researchers from the University of California and University of Chicago have not only created a solid-state battery, but one using sodium instead of lithium, and without even an anode.

나트륨 배터리

Sodium is a very abundant ion, virtually in unlimited amounts in the ocean, 1,000x more abundant on Earth’s crust than lithium. This makes it a very good alternative to lithium.

It is important because lithium is hitting several limitations due to the EV boom:

• It is too expensive, making electrification itself too expensive.
• Its extraction is environmentally damaging.
• Produced only in a few places in the world and mostly refined in China, causing geopolitical risks.

Because it is so omnipresent and abundant, it is very unlikely that sodium will ever experience the price instability and shortage that lithium experienced in the last years.

The issue is that sodium batteries are usually not really dense enough to compete with lithium-based batteries, except for low-price EV models.

양극 프리 배터리

Normally, a battery has an anode that stores the ions while the battery is charging. They then flow back toward the cathode when the battery is releasing its energy.

Anode-free batteries instead store the ions in an electrochemical deposit of alkali metal directly on the current collector.

This allows for higher cell voltage, lower cell cost, and increased energy density.

Source: University Of Chicago

The issue with an anode-free design is that the current collector tends to see a deposit build-up from the liquid electrolyte, leading to damaging the battery.

고체 전지

Solid-state batteries have long been expected to be the “final” form of battery-based energy storage, especially for applications requiring very high-density mobility.

Removing the electrolyte reduces the total battery weight and makes the battery very quick to charge and discharge.

The issue with these designs is usually to manage to have a solid enough system, as metals tend to swell when charging.

In addition, the issue of growing dendrites that can create shortcuts (and therefore fire) is always looming in the background, like with lithium-ion batteries.

양극 프리 나트륨 고체 상태

In the context of an anode-free design, an additional issue is that a classical solid electrolyte cannot properly interact with the current collector.

The researchers solved this issue by using aluminum powder as a current collector, which is a solid that can flow like a liquid.

Source: University Of Chicago

많은 이점

By being solid, the aluminum electrolyte also prevents the formation of dendrites, the main cause of too short lifespan of solid-state batteries.

It also provides a stable interface and avoids to see some of the sodium inaccessible to the current which would reduce the battery capacity.

Lastly, it allows for high energy density, with the different options for this sodium-solid-state battery ranging all in the 200-400Wh/kg density.

Source: University Of Chicago

While this is a bit lower than lithium-based solid-state batteries, it is still a lot stronger than currently used batteries. Combined with the economics of much cheaper materials, with sodium and aluminum replacing lithium, cobalt, and nickel, it could be a winning combination.

조합의 힘

Even a few years ago, the idea of sodium batteries, or anode-free batteries, was only a concept that many doubted would reach a commercial stage. The same can be said for solid-state batteries.

This is quickly changing for every one of these categories, as well as plenty of other potential chemistries and designs we explored in our articles “The Future Of Energy Storage – Utility-Scale Batteries Tech” and “The Future Of Mobility – Battery Tech”.

It seems we are entering a new stage, where researchers are now looking at all these now-proven battery concepts and starting to merge them together.

Surprisingly, it might help overcome the individual limitations of each idea.

In this example, both solid-state batteries’ dendrite issues and anode-free design’s issue of deposit on the current collector get solved by using aluminum powder.

Aluminum powder alone on an anode-free design would still yield too low density.

Aluminum powder in solid-state batteries would not be cheap enough without using sodium.

Meanwhile, sodium alone is cheap but not dense enough to meet the requirement for mobility.

So it seems that combining different design elements can help bring together their respective advantages while also removing or at least attenuating their individual issues, creating a much larger set of future opportunities for innovative battery chemistries than previously thought.

나트륨 배터리 기업

1. CATL

CATL is the global leader in battery manufacturing, producing more than half of the global battery volume. The company is present at every step of the battery manufacturing supply chain and is a leader in battery technology.

This is true for lithium-ion batteries, where the company has been a long-established leader for a long time. CATL has also announced impressive progress on multiple other battery types :

• A 12,000-cycle ultra-long-life battery for utility-scale energy storage, with 18,000 cycles as a long-term goal.
• A 700km LFP (Lithium Ferrum Phosphate) battery charging 400km of range in 10 minutes.
• A 500 Wh/kg, potentially enabling electrification of passenger aircraft.
• Mass production of 160Wh/kg sodium-ion batteries, with a target for 200 Wh/kg.

Source: CATL

The company is getting active in the utility-scale battery market, with the announcement of its TENER system performance. It is “the world’s first mass-producible energy storage system with zero degradation in the first five years of use in Beijing, China”.

Immense Energy in a Compact Space: 20-foot Container with 6.25 MWh Capacity

Powered by cutting-edge technologies and extreme manufacturing capabilities, CATL has resolved the challenges caused by highly active lithium metals in zero-degradation batteries, which effectively helps prevent thermal runaway caused by oxidation reactions.

CATL has also invested 3.25B in battery recycling capacities in China. CATL has notably achieved a remarkable recovery rate of 99.6% for nickel, cobalt, manganese, and 91% for lithium.

Thanks to its scale, focus, and R&D achievements, CATL is likely to be at the forefront of battery innovation, manufacturing, and recycling. This makes it a key partner for EV manufacturers, including Tesla (TSLA ), NIO, Ford, Stellantis, etc.

2. BYD

A long-time challenger of Tesla in the EV market, BYD has become a serious competitor not only for Tesla but for virtually all automakers.

The company evolved from its origin as a phone battery supplier to selling almost as many EVs as Tesla in China (the world’s largest EV market) and being the best-selling EV in Thailand, Sweden, Australia, New Zealand, Singapore, Israel, and Brazil.

BYD is a large part of why China suddenly became the world’s largest car exporter in 2023, surpassing Japan. The company’s aggressive overseas expansion is also carried by new factories, like in Hungary.

And with the release of $10,000-$12,000 cars like the Seagul, using sodium batteries, a whole new market might open for BYD EVs.

Source: By User3204 – Own work, CC BY-SA 4.0, https://commons.wikimedia.org/w/index.php?curid=142412738

Still at its core, a battery manufacturer, BYD is a serious challenger to CATL in the LFP battery market, with a 41.1% market share in China (compared to CATL’s 33.9%).

The “flood” of cheap EVs produced by BYD into the European and American markets is likely to be met with some level of protectionism (even above the recently imposed tariffs), which could hinder BYD’s growth.

But at the same time, cheap Chinese EVs are already a great success in the rest of the world, which does not have incumbents much in the way of domestic automakers to protect, including the entirety of South America, Russia, Africa, the Middle East, and Southeast Asia.

This represents several billion potential customers for BYD, living in countries eager to strike a geopolitical balance and stay on good terms with both the West and China, so it is unlikely to create too strong protectionist barriers.

And even in the EU or the USA, BYD might stay competitive, thanks to the much higher prices of local EV manufacturers compared to prices in China, as well as localization of the production out of China for these markets, like, for example, in Eastern Europe, Mexico, or Turkey.