Sulfide Electrolyte Solid-State Battery Revolution in SNEC Expo 2025

Solid-State Battery Advancements and Battery Innovation Exhibited at SNEC Expo

As the sulfide-based solid-state battery moves closer to commercialization, the supporting technologies around it—particularly the current collector—are experiencing transformative innovation. With the unique demands of sulfide electrolyte solid-state battery systems, traditional materials are giving way to advanced solutions like nickel coating on copper foils, 3D copper foil structures, and even composite current collector designs that aim to balance durability, weight, and performance. These innovations are not just technical upgrades—they are foundational shifts required for compatibility with dry electrode processes, which are essential for scaling next-gen batteries. At SNEC 2025 in Shanghai, this momentum was on full display, with industry leaders showcasing breakthrough materials and architectures, including the debut of 0BB technology, a concept adapted from Photovoltaics and now applied to enhance battery assembly efficiency. The synergy of solid-state battery advancements and battery innovation exhibited at SNEC Expo signals a new era for sulfide electrolyte-based designs, with the current collector emerging as a silent enabler of high-energy, safe, and commercially viable energy storage.

Solid-State Batteries Enter the Final Stretch Toward Commercialization

The battery industry is abuzz with enthusiasm over sulfide-based solid-state batteries, often referred to as being in the “last mile” before mass production. However, industry experts caution that the reality is more nuanced. One area drawing scrutiny is the role of current collectors, which appear to be undergoing a fundamental transformation rather than following a straightforward upgrade path.

Why the Current Collector Matters More Than Ever

Traditionally, current collectors were expected to be thin, strong, and flexible. But with the advent of solid-state technology, the demands have evolved to include high-temperature resistance, corrosion resistance, and even "de-metalization." This shift underscores the key role of current collectors in enabling next-generation battery performance and stability.

Nickel-Coated Copper Foils: A Practical Interim Solution

To combat sulfide corrosion and silicon or lithium-metal electrode expansion, companies like Nord Co. have introduced double-sided nickel-coated copper foils. These foils withstand up to 150°C for over 30 hours, and 200°C for 24 hours, without oxidation. The nickel layer also prevents delamination caused by mismatched thermal expansion between materials. This approach offers a balance between cost, performance, and manufacturability.

Composite Current Collectors: Lightweight and Safer

Composite current collectors are gaining attention due to their safety and lightweight nature. Companies like Jemai Electronics and UnionTech are developing integrated solutions that combine current collectors and lithium-metal anodes. These innovations are helping boost energy density while reducing the overall weight of battery packs.

3D and Porous Structures: A New Era for Current Collectors

Researchers and startups are moving towards three-dimensional current collectors. Foam-based structures made from copper or nickel provide more surface area and allow for better accommodation of electrode expansion. Companies like Delfu Technology have begun commercializing porous copper foils using advanced methods like laser perforation and chemical etching.

Gradient-Structured and Carbon-Based Alternatives

Stanford and Tsinghua University researchers are exploring porous carbon-based collectors using graphene and carbon nanotubes. These materials offer extremely low mass and eliminate the risk of metal corrosion. However, challenges like electrode tab welding must be resolved before mass adoption.

Dry Electrode Technology and Integration Challenges

Dry electrode manufacturing is seen as a clean, efficient, and high-performance method, but it brings challenges for current collector compatibility. Since there’s no liquid binder, achieving a strong bond between the electrode and collector is difficult. Emerging technologies like XinYuren’s “dry powder direct coating” system apply conductive glue before thermal rolling, showing promise for next-gen production lines.

Cross-Sector Coordination is Crucial

Despite numerous innovations, scaling remains difficult due to a lack of coordination between materials, equipment, and manufacturing processes. For instance, composite current collectors have been in development for years but haven’t achieved widespread application. Synchronizing advancements across the battery value chain remains a key hurdle.

Conclusion: Innovation in Progress, Breakthroughs Pending

The evolution of current collectors encapsulates the broader complexity of solid-state battery commercialization. Whether it’s metal-coated foils, 3D structures, or carbon-based composites, each solution solves a specific issue but introduces new ones. Only through continued cross-disciplinary collaboration can the industry truly unlock the potential of solid-state batteries.