Navigating the future of battery tech: Solid-state batteries

• Cell redesign: Unlocking next-generation materials
• Beyond Li-ion: Elevating safety and range for future e-mobility
• Challenges ahead: Maintaining conductivity with solid electrolytes

As we enter a new era of electrification the question of “Where is battery tech going next?” becomes increasingly pertinent. With advancements in materials science and engineering, the future of battery technology promises enhanced performance, safety and sustainability, potentially revolutionizing fast-growing sectors, from passenger EVs and grid storage to other forms of transportation such as airplanes and ships. This article is the first edition of a three-part series exploring a selection of the most relevant cutting-edge battery technologies on the horizon, their potential impacts on the lithium-ion (Li-ion) incumbent, and the timeline for their development and commercialization.

Challenges of current Li-ion batteries

Current Li-ion battery technology, particularly Nickel Manganese Cobalt (NMC) and Lithium Iron Phosphate (LFP) battery types encounter several challenges that limit their lifespan and overall performance. NMC batteries, while offering high energy density and power capacity, struggle with issues related to thermal instability and safety concerns. On the other hand, LFP batteries, known for their safety and longer cycle life, are constrained by their lower energy density compared to NMC batteries. This limitation impacts their suitability for energy-intensive applications, such as electric vehicles, where space and weight constraints demand high energy density for extended range and performance. Meeting these challenges requires redesigning the battery cell and its constituent components.

What makes this battery different?

Solid-state batteries (SSBs) are a group of lithium-based batteries that use a solid – rather than liquid – electrolyte, which mixes directly with the cathode. This is a significant design change since electrolytes are critical battery components that enable ion transport between the anode and cathode. Electrolyte properties directly affect a battery’s performance, including energy capacity, power density, and cycle life. Conventional Li-ion batteries generally use a lithium salt dissolved in an organic solvent as an electrolyte. The main categorization among SSBs is the type of solid electrolyte utilized, with polymer, ceramic-oxide, and sulfide types being the most prevalent. Many SSBs with different combinations of cathodes, anodes, electrolytes and additives have been investigated over the past decades.

Semi-solid-state batteries (SSSBs) occupy a middle ground between traditional liquid electrolyte batteries and SSBs, with a gel-like substance for an electrolyte. Both SSBs and SSSBs may use the same types of cathode materials as conventional Li-ion e.g., NMC and LFP. Notably, high-nickel NMC cathodes in oxide-based SSBs are preferred for their high energy densities. SSBs and SSSBs can also use graphite as an anode but other, more advanced materials such as lithium metal and silicon are generally preferred.

The most obvious advantage of SSBs is the replacement of the liquid electrolyte, composed of flammable organic solvents, with a solid – drastically improving safety and handling.[1] While lithium metal provides the highest specific capacity as an anode material, achieving stable and uniform lithium deposition during battery operation remains a challenge, impacting the overall efficiency and safety of SSBs. At present, QuantumScape’s has developed a battery composed of a an energy density of 800-1000 Wh/l. [4] Improved energy density has the potential to increase EV range significantly, making EVs more attractive to consumers worried about range and charging infrastructure, increasing EV penetration into passenger vehicles.

What challenges do these batteries face?

Key areas of improvement for SSBs include enhancing the ionic conductivity while maintaining the stability of the solid electrolyte. Ionic conductivity is a measure of the flow of ions through a material when an electric potential is applied. A higher ionic conductivity allows for faster charging and discharging cycles and improves the overall efficiency and performance of the battery. Currently available polymer electrolytes, while inexpensive and relatively easy to manufacture, exhibit low ionic conductivities at room temperature, limiting their use. Innovations to increase ionic conductivity include hybrid designs combining polymer with ceramic materials to enhance conductivity. [6]

Stability and cycle life issues further complicate SSB advancement. Operating for extended periods at high voltages and utilizing anode materials such as lithium metal and silicon demands rigorous mechanical strength properties to resist dendrite penetration. Dendrites can pose safety risks by causing internal short circuits and shorter cycle life due to loss of active material and electrolyte decomposition, particularly for less stable sulfide-based solid electrolytes. [1] [5] Achieving long-term stability and preventing dendrite formation while achieving high energy densities are therefore crucial for the success of SSBs. [2]

Manufacturing costs of SSBs also pose a significant barrier to their development and commercialization. The high reactivity of lithium metal with moisture and oxygen requires stringent safety measures during manufacturing, increasing costs. [3] Additionally, solid electrolytes made from ceramics or polymers often require intricate production techniques. Consequently, initial SSB costs are expected to exceed those of Li-ion batteries, driven by more complex production processes of these new materials. Although there is significant uncertainty about how this will translate to final cell cost at large-scale commercialization, addressing these manufacturing challenges is essential to make SSBs a competitive option in the battery market.

Apricum’s takeaway

Although currently SSBs and SSSBs occupy niches in commercial vehicles, such as buses, the mainstream EV market is anticipated to be a major beneficiary of solid-state battery technology advancements. This is due to the promise of longer ranges, faster charging times, and enhanced safety compared to traditional lithium-ion batteries. Regarding the future market outlook, the production of SSBs is now under 2 GWh worldwide and predominantly based on polymer electrolytes. A notable increase in production capacity is expected from 2025 to 2030 as batteries with oxide and sulfide electrolytes enter the market. By 2030, the production capacity of SSBs is projected to range from 15 to 55 GWh, expanding further to between 40 and 120 GWh by 2035. By then, the market share of SSBs will remain a small fraction of the total Li-ion battery market of approximately one to two percent. [1]

Summary

Solid-state batteries (SSBs), characterized by their solid electrolytes, are emerging as a focal point due to their enhanced safety profile and the opportunity to incorporate high-capacity anodes like lithium metal, offering a leap in energy density. Despite the advantages, hurdles such as ionic conductivity, dendrite formation, and elevated manufacturing costs pose significant challenges. As with all new technologies, the optimistic projections for the commercialization of SSBs must be tempered with a realistic assessment of the current technological challenges and the pace of innovation in battery materials and manufacturing processes. While lithium-ion batteries will continue to dominate the market in the near term, ongoing research into these novel battery technologies is crucial for ushering in a more sustainable and efficient future in energy storage.

How Apricum can help

Apricum exclusively services the cleantech and renewables industries. We have exceptional experience and knowledge including the battery sector, covering both up and downstream value chains. Our unique blend of strategy consulting and transaction advisory helps clients with both direction and execution. Over 14 years we have delivered over 350 successful projects in 30 countries. We offer a complete spectrum of services in strategy consulting from technology assessment, market screening, value chain analysis, business model development, and due diligence to investment banking (corporate and asset M&A, debt and equity fundraising, and corporate finance). If you would like to learn more about how we can support your company in entering or expanding your activities in the energy storage sector, please contact Apricum Partner Florian Mayr.

[1] https://www.isi.fraunhofer.de/content/dam/isi/dokumente/cct/2022/SSB_Roadmap.pdf

[2] https://www.isi.fraunhofer.de/en/blog/themen/batterie-update/feststoffbatterien-markt-potenziale-herausforderungen-materialien-komponenten-zellkonzepte.html

[3] https://www.theguardian.com/environment/2024/feb/04/solid-state-batteries-inside-the-race-to-transform-the-science-of-electric-vehicles

[4] https://www.quantumscape.com/technology/#energydensity

[5] https://seas.harvard.edu/news/2024/01/solid-state-battery-design-charges-minutes-lasts-thousands-cycles

[6] https://pubs.rsc.org/en/content/articlelanding/2021/ta/d0ta11679c

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