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배터리 혁신, 고체 전해질 변형을 현실에 한 걸음 더 가깝게 만든다

게시일 2024년 10월 9일

업데이트일 2026년 5월 31일

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Jonathan Schramm

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고체 전해질 배터리가 전기차 지배를 달성한다

While lithium-ion batteries have become the dominant solution for EV battery systems, they suffer from a few limitations.

그 중 하나는 아직 충분히 높은 에너지 밀도가 아니며, 또 다른 하나는 배터리를 관통하는 수지상(덴드라이트) 성장과 전해질이 화재를 일으킬 수 있는 안전 문제입니다.

출처: Nobel Prize

두 문제 모두 고체 전해질 배터리를 사용하면 전해질이 필요 없고 수지상(덴드라이트) 위험도 사라지므로 완화될 것으로 기대됩니다.

토요타는 2027년까지 이러한 고체 전해질 배터리 사용을 예측하고 있습니다, 그리고 전반적으로 이는 모빌리티의 미래에 대한 견고한 후보로 보입니다.

하지만 여전히 문제가 남아 있는데, 특히 가넷형 고체 전해질(리튬 7 라나트 3 지르코늄 2 산소 12, LLZO라고도 함)과 관련됩니다(아래 참고).

캐나다 맥길 대학교의 네 명 연구진이 에너지 용량을 높일 수 있는 새로운 LLZO 설계를 만들었다는 소식은 좋은 소식입니다. 그들은 Cell Reports Physical Science에 ‘4.8-V all-solid-state garnet-based lithium-metal batteries with stable interface’라는 논문으로 결과를 발표했습니다.

고체 전해질

LLZO

It is usually said that solid-state batteries do not need electrolytes. This is technically correct when referring to the liquid electrolyte commonly used in lithium-ion batteries.

하지만 물론, 모든 배터리는 양극과 음극 사이에 어느 정도의 연결 고리가 필요합니다. 고체 전해질(SE)에는 세 가지 유형이 있습니다: 세라믹, 폴리머, 그리고 복합 SE(CSE).

The composite solid-state electrolytes (CSEs) mix polymer SE with ionic conductive inorganic fillers like Li7La3Zr2O12 (LLZO) to facilitate lithium-ion transports.

While this method is ideal for high-voltage operation in dense batteries, it suffers from poor contact with the electrode, reducing the overall efficiency.

다공성 LLZO

What the researchers discovered, is that the LLZO can be made of a porous ceramic membrane, instead of the usual sense plate. In more technical terms:

Here, we design a highly conductive and interface-friendly garnet-based composite solid electrolyte (CSE) comprising a cubic Li6.1Al0.3La3Zr2O12 porous framework and polyvinylidene difluoride (PVDF) with a three-dimensional continuous structure.

Visually, it translates into a very complex 3D structure full of small holes at the microscopic scale:

출처: Cell

이 구조는 리튬 이온에 많은 표면 접촉을 제공하면서도 전극에 강한 부착성을 유지합니다.

출처: Cell

보다 안정적이고 내구성 있는 배터리

Solid-state batteries are overall a lot more powerful and energy-dense than lithium-ion batteries. But they have been difficult to manufacture at scale so that they can last many charge-discharge cycles without losing capacity.

그래서 연구진은 배터리를 테스트하여 만든 전극 인터페이스가 기대만큼 견고한지 확인했습니다.

200 사이클 후 현미경으로 관찰했을 때 균열, 박리 등과 같은 열화 흔적이 전혀 발견되지 않았습니다.

출처: Cell

Overall, the battery prototype demonstrates excellent resistance, especially against dendrite formation.

Li-Li symmetric cells based on the ceramic-based CSE can cycle stably for 1,000 h at 0.1 and 0.5 mA cm−2, indicating excellent electrochemical stability against Li-metal and even Li+ deposition (dendrite suppression).

향상된 안전성 프로파일

The drastically reduced dendrite formation, as well as the absence of flammable electrolytes, should help increase significantly the safety of lithium batteries.

세라믹 기반 CSE의 두께가 단 125μm에 불과하기 때문에, 이 기술은 매우 고에너지 밀도의 고체 전해질 배터리를 만드는 데 매우 경쟁력이 있습니다.

또한, 개선된 LLZO를 만드는 기술이 간단하지는 않지만 희귀 금속, 특수 장비, 혹은 배터리 제조에서 일반적이지 않은 복잡한 공정을 필요로 하지 않는다는 점도 주목할 만합니다.

출처: Cell

따라서 전반적으로 이는 고체 전해질 배터리의 안정성, 안전성, 에너지 밀도 및 생산 용이성 등 모든 중요한 측면을 더욱 향상시키는 중요한 단계가 될 것입니다.

고체 전해질 배터리가 승리하고 있는가?

It is not to say that solid-state batteries are certain to become the new standard for EV batteries in the coming years.

Lithium-ion batteries might be able to compete as well. This is mostly linked to improvement in the design, with similar nanopores helping in reducing dendrite formations.

Most notably, honeycomb batteries developed by battery manufacturing global leader CATL might reach a safety profile and energy density similar to some solid-state batteries.

Overall, it seems that a deeper understanding of battery material, especially at the micro- and nano-scale, and the uses of nanopores will be the way forward to keep improving battery performances and remove for good the risk caused by dendrite formation.

배터리 기술에 투자하기

Lithium batteries have already changed the world several times, from allowing people to carry advanced electronics everywhere to powering cars with electricity only.

They might still do so again, or other types of batteries, by allowing for a 100% renewable power grid or allowing for airplane electrification when reaching a high enough energy density.

You can invest in battery-related companies through many brokers, and you can find here, on securities.io, our recommendations for the best brokers in the USA, Canada, Australia, the UK, as well as many other countries.

If you are not interested in picking specific battery companies, you can also look into biotech ETFs like Amplify Lithium & Battery Technology ETF (BATT), Global X’s Lithium & Battery Tech ETF (LIT), or the WisdomTree Battery Solutions UCITS ETF, which will provide a more diversified exposure to capitalize on the growing battery industry.

고체 전해질 기업

(QS )

Long expected to be the one of the first companies to bring solid-state batteries to the market, QuantumScape has been at the forefront of the development of this technology.

QuantumScape batteries are using lithium metal, anode-fee batteries.

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.

출처: QuantumScape

(we also discussed the concept of anode-free batteries in the context of sodium batteries in “Anode-Free Sodium Solid-State Batteries Could Reduce Reliance on the ‘Lithium Triangle”).

QuantumScape has however regularly delayed the expected date of mass production of its batteries, dampening the initial enthusiasm of investors for the company.

This might be changing with a few key developments in 2023 & 2024:

생산 일관성 및 품질 향상.
포장 설계 개선, 내부 여유 공간 축소, 얇은 전류 수집체 및 슬림한 프레임 포함.
고양극 적재량 유닛 셀을 자동차 OEM(Original Equipment Manufacturer) 파트너에게 공급.
QSE-5 출시를 발표했으며, 이는 자동차 분야의 잠재적 고객을 위한 회사 최초의 상용 제품입니다.

Overall, QuantumScape seems to be by far the solid-state company with the most mature technology, especially when it comes to the durability of the battery.

출처: QuantumScape

폭스바겐과의 협력

More importantly, the company is showing real progress in establishing a partnership with Volkswagen, the 2^nd largest automaker in the world.

2024년 7월, QuantumScape는 폭스바겐과 QSE-5 설계 기반 배터리 셀 제조 협력을 위한 계약을 체결했습니다.

The license would allow PowerCo to manufacture and sell automotive batteries up to 40 GWh annually, expandable by an additional 40 GWh.

This is a non-exclusive, royalty-bearing IP license, allowing QuantumScape to keep selling to any other potential client.

Maybe more importantly to alleviate investors’ anxieties about the company, it will also give an initial royalty fee of $130M, credited against future royalties, paid by PowerCo, Volkswagen’s battery subsidiary.

This gives the company an additional 18 months of cash runways compared to previous guidance, going well into 2028 by now.

It should be more than enough time to ramp up production and start registering solid revenues.

So as long as QuantumScape batteries perform adequately, they should be able to find their niche in the market alongside batteries manufactured by larger companies like CATL, BYD, and Panasonic.

Considering that Volkswagen has likely extensively tested its own QuantumScape prototypes and studied the production ramp-up, the recent agreement seems quite a solid endorsement of the company’s technology.