By Lucas Bettle 

 

Increasing adoption of electric vehicles (EVs) over the coming years will continue to put significant demand on lithium-ion battery production. However, solid-state batteries are a promising technology that could replace lithium-ion batteries in the near future. This technology stands to significantly improve performance while also reducing the environmental and social impacts associated with EV battery material sourcing. While not yet at the stage of commercial production, there is significant government investment and industry development currently underway.

​

Comparison of Lithium-Ion and Solid-State Battery Technologies

Conventional lithium-ion batteries rely on an oxide or phosphate cathode, graphite anode, and lithium salt in a liquid organic solvent as an electrolyte. Liquid electrolytes easily spread over and penetrate electrode materials, allowing for high ionic conductivity to facilitate charge transfer and power delivery. However, they are highly volatile and flammable, creating potential safety hazards. (Vu, 2023)

Solid-state batteries instead rely on a lithium metal anode, various oxide or sulfide cathodes, and solid ceramic or polymer electrolytes. This significantly improves safety, as there is no flammable liquid present. Ceramic electrolytes are emerging as the primary contender for the first generation of solid-state battery EVs. Most of the potential electrolyte materials are lithium oxides or sulfides, although there are also more complex lithium compounds and alternatives, such as NASICON, which is sodium-based. (Vu, 2023)

All-solid-state batteries feature an entirely solid electrolyte without any liquid present. Hybrid solid-state batteries consist of a ceramic solid electrolyte in contact with a liquid electrolyte, aiming to improve ionic conductivity. A hybrid approach solves some challenges but also retains many of the downsides of liquid electrolyte batteries. (Woolley, 2022)

​

Performance of Solid-State Batteries

Solid-state batteries stand to significantly increase the energy density and range available for EVs. Lithium-ion batteries have a theoretical energy density of 387 Wh/kg. The theoretical energy density of solid-state batteries using lithium metal anodes increases to 534 Wh/kg. (Troy, 2015) Various automakers have released targets for the range of their planned production vehicles, with Honda, Toyota, and Mercedes-Benz all stating 620 miles, more than double the typical range of current lithium-ion battery EVs.

However, there are some technical challenges that make reaching this theoretical performance difficult. One of the most significant challenges is low ionic conductivity in solids compared to liquid electrolytes. Maintaining solid-solid interfacial contact between electrodes and electrolytes is also much more difficult than working with liquid electrolytes. (Vu, 2023)

Solid-state batteries can suffer several types of degradation at solid-solid interfaces. Lithium anodes are prone to develop dendrites, needle-like structures that form during charging. Voids can form at interfaces, severely impacting performance. Interfaces are also susceptible to physical stress during vehicle operation. (Zaman, 2022)

​

Different electrolyte materials have their own benefits and challenges. Oxides have high electrochemical stability and voltage but are inflexible and expensive. Sulfides are highly conductive and flexible but have low oxidation stability and poor compatibility with many cathode materials. Both hydrides and halides show exceptional stability with lithium metal anodes but are highly sensitive to moisture. (Manthiram, 2017)

​

Environmental and Social Impacts of Solid-State Batteries

Solid-state batteries vary in the composition of their anodes, cathodes, and electrolytes, with each relying on different combinations of minerals. Lithium nickel manganese cobalt oxides (Li-NMC) are the most widely used lithium-ion battery chemistry in EVs with lithium iron phosphate (LFP) gaining market share. Solid-state batteries rely on a lithium metal anode, primarily with lithium phosphorus sulfide (LPS) electrolytes and a variety of cathode materials. (Popien, 2022)

​

All major solid-state battery chemistries reduce metal resource depletion compared to Li-NMC batteries. While Li-LFP outperforms some solid-state battery chemistries, solid-state batteries with LFP or sulfur cathodes have significantly reduced metal resource depletion compared to Li-LFP. (Popien, 2022)

​

The sourcing of minerals from regions that engage in child labor and forced labor has been among the most prominent concerns in EV battery supply chains. Avoiding graphite as an anode material significantly reduces the risk of child labor and forced labor in battery production. (Popien, 2022)

​

Lithium remains a significant source of risk for solid-state batteries due to its use in electrolytes, anodes, and some cathodes. Solid-state batteries with sulfur cathodes have lower risks due to the reduced requirement for lithium. Other critical minerals involved in production include cobalt, nickel, lanthanum, and cerium. (Popien, 2022) 

​

Solid-State Battery Manufacturing Challenges

Lithium-ion battery manufacturing is relatively straightforward and scalable. Anodes and cathodes are manufactured by mixing an “ink” containing the active material and a polymer binder, which is then coated onto the charge collector. The electrodes and separator are then flooded with the liquid electrolyte. (Hatzell, 2021)

​

Solid-state battery manufacturing is considerably more challenging. Solid electrolytes must be incredibly thin to achieve greater or equal energy density than lithium-ion batteries, in the range of 40 to 225 micrometers. There are many potential manufacturing methods being explored, but most involve complex and precise steps, including tape-casting ceramic slurry, sintering the cathode at high temperatures, and then applying the electrolyte via a deposition process. (Hatzell, 2021)

​

Controlling the electrolyte thickness, electrode microstructure, and interface quality are all key challenges that manufacturers must overcome to ensure ionic conductivity, durability, and longevity. (Hatzell, 2021)

​

Current State of Industry Adoption

Solid-state batteries have been used in certain applications that require high levels of safety and reliability, such as pacemakers and hearing aids, for decades. However, their use in larger-scale applications such as EV batteries is still an ongoing development, with production vehicles using the technology yet to hit the road.

​

Governments around the world are investing heavily in solid-state battery research. China has announced investments of more than $830 million. (Reuters, 2024) The U.S. Department of Energy has invested $16 million specifically in solid-state battery research. (Department of Energy, 2023) However, the Department of Energy has also announced over $3 billion for advanced batteries and battery materials in general, much of which may focus on solid-state batteries. (Department of Energy, 2024)

​

The automotive industry is well underway in solid-state battery research, with many manufacturers planning to roll out production models over the coming years. Honda began production at a demo facility in January 2025 with a target of 2030 for full production. (Dnistran, 2024)

Nissan aims to launch solid-state EVs by 2029, with a pilot plant expected to start production in 2025. (Leussink, 2024) Hyundai is aiming for mass production in 2030, with a pilot facility also starting production in 2025. (Kothari, 2025)

​

Toyota hopes to implement solid-state batteries in EVs as soon as 2027. Toyota has also stated potential fast-charging from 10 percent to 80 percent in under 10 minutes. (Crisara, 2025)

​

In February 2025, Mercedes-Benz began testing a prototype sedan using a semi-solid-state battery that relies on a solid matrix infused with a liquid or gel electrolyte. (MacKenzie, 2025) Stellantis plans to launch a demonstration fleet of EVs with solid-state batteries by 2026. (Reuters, 2024)

​

Promising Outlook for Solid-State Batteries in the Face of Ongoing Challenges

Solid-state batteries represent a promising step forward in EV technology, improving performance, safety, and environmental impact. However, these promises have yet to be realized and there are technical challenges yet to be solved. Substantial government and private-sector investment is being put toward the development of this burgeoning technology. If successful, solid-state batteries stand to have a profound positive impact on the EV industry.

​

References

1. Crisara, M. (2025, February 26). An Astonishing Solid-State Battery May Let EVs Recharge as Fast as Refueling In Just 2 Years. Popular Mechanics.

2. Department of Energy. (2023, September 14). Department of Energy Announces $16 Million to Boost Domestic Capabilities in Solid-State and Flow Battery Manufacturing.

3. Department of Energy. (2024, December 19). U.S. Department of Energy Selects 11 Projects to Advance Domestic Manufacturing of Next-Generation Batteries.

4. Dnistran, I. (2024, December 06). ‘Game Changer’: Honda Solid-State EVs With 620 Miles Of Range Coming This Decade. InsideEvs.

5. Hatzell, K. (2021). Prospects on large-scale manufacturing of solid-state batteries. MRS Energy & Sustainability.

6. Kothari, S. (2025, February 12). Hyundai May Reveal Its Game-Changing Solid State Battery In March: Report. InsideEvs.

7. Leussink, D. (2024, April 16). Japan’s Nissan bets on solid-state batteries, gigacasting for next-gen EVs. Reuters.

8. Liu, Z. (2024). Are solid-state batteries absolutely more environmentally friendly compared to traditional batteries-analyzing from the footprint family viewpoint. Journal of Cleaner Production.

9. MacKenzie, A. (2025, February 25). The Mercedes-Benz EQS Claims 620 Miles of Range in Semi-Solid-State Battery Testing. MotorTrend.

10. Manthiram, A. (2017). Lithium battery chemistries enabled by solid-state electrolytes. Nature Reviews Materials.

11. Popien, J.-L. (2022). Comparative sustainability assessment of lithium-ion, lithium-sulfur, and all-solid-state traction batteries. The International Journal of Life Cycle Assessment.

12. Ren, D. (2023). Challenges and opportunities of practical sulfide-based all-solid-state batteries. eTransportation.

13. Reuters. (2024, May 20). China to invest more than $830 mln in solid-state battery research -source. Reuters.

14. Reuters. (2024, October 23). Stellantis to launch fleet of EVs fitted with Factorial solid-state batteries. Reuters.

15. Troy, S. (2015). Life Cycle Assessment and resource analysis of all-solid-state batteries. Applied Energy.

16. Vu, T. T. (2023). Hybrid electrolytes for solid-state lithium batteries: Challenges, progress, and prospects. Energy Storage Materials.

17. Woolley, H. M. (2022). Hybrid solid electrolyte-liquid electrolyte systems for (almost) solid-state batteries: Why, how, and where to? Royal Society of Chemistry.

18. Zaman, W. (2022). Processing and manufacturing of next generation lithium-based all solid-state batteries. Current Opinion in Solid State and Materials Science.