Author: Dr Alex Holland, Research Director at IDTechEx
Amongst the wide range of next-generation battery technologies being developed, silicon anodes are one of the most promising routes to improved Li-ion batteries. Due to their high capacity, silicon anodes can enable Li-ion energy densities above 1000 Wh/l and 400 Wh/kg, while rate capability and charging times can also be improved. However, achieving long-term cycle stability has been a significant challenge due to the expansion of silicon under lithiation. A range of silicon anode technologies are being developed, which aim to improve battery performance whilst overcoming the poor cycle life historically typical for silicon anode materials. IDTechEx’s report, “Silicon Anode Battery Technologies and Markets 2025-2035: Players, Technologies, Applications, Markets, Forecasts”, provides in-depth analysis and discussion of silicon anode technologies, the silicon anode market, and key players and start-ups.
Silicon Oxide (SiOx) Anodes
The oxide matrix helps mitigate the volume expansion of silicon, which is also less drastic than pure silicon material, making it a more durable alternative to pure silicon. SiOx materials can also form a more stable SEI (solid electrolyte interphase) layer to limit electrolyte decomposition and also act as a buffer to volume expansion. Due to these benefits, SiOx materials are already in commercial use, including in electric vehicle batteries, where SiOx can be added as an additive to graphite anodes. However, SiOx materials can suffer from low initial coulombic efficiencies, which can limit cycle life and create difficulties in cell design. The conductivity of silicon oxides is also relatively low, inhibiting rate capability and charging times. Routes to overcome this include the use of metal dopants, pre-lithiation techniques, and carbon coatings. Companies such as Daejoo Electronic Materials are developing silicon oxide materials with higher efficiency and rate capability.
Silicon-Carbon and Silicon-Graphite Composites
Silicon-carbon composites aim to balance the high capacity of silicon with a stabilizing carbon material. These materials often incorporate silicon into a porous carbon structure enhancing conductivity and providing space for the volume expansion of silicon. These materials can then be blended with conventional graphite anode material. Importantly, the improved stability on offer from these silicon-carbon composites also allow their use at higher weight percentages whilst maintaining good cycle life. Numerous companies are developing compositions where silicon carbon constitutes the majority of the anode active material, and these materials are now being commercialized. For example, composites from Group14 Technologies have been deployed in smartphones, while Sila Nano material has also been used in consumer electronic devices. The performance and qualification requirements for electric vehicles are more stringent than for electronic devices, but the energy density and fast charge benefits on offer, coupled with increasing evidence of suitable cycle life, make these silicon-carbon composites an attractive proposition for deployment in electric vehicles in the short-medium term.
100% Silicon Anodes
SiOx and Si-C and Si-Gr materials can help to overcome the key disadvantages of silicon regarding their poor cycle life. However, they also limit the amount of active silicon material used, thus limiting the overall energy density benefit of silicon. One approach to maximizing the amount of active silicon material comes from the use of CVD to deposit silicon nanowires and structures directly onto current collector foils. The oriented silicon structure and connection to the current collector can maximize energy density and enhance rate capability, though these materials can still suffer from poor stability and are expected to be expensive in the short term. Other companies are exploring routes to producing nanostructured silicon powders from lower-cost feedstocks and methods. For these materials, coating, binder, electrolyte, and cell design will be critical to ensuring suitable cycle life and stability.
There are various silicon anode material technologies being developed and commercialized to enable more widespread use and at higher weight percentages. Source: IDTechEx – adapted from Group14 Technologies, FIC Advanced Materials, Daejoo Electronic Materials, Amprius, E-magy
Conclusion
Silicon anode technology is a key focus in the advancement of lithium-ion batteries, offering the potential for higher energy densities, higher power, and faster charging batteries. While silicon oxides and silicon-carbon composites, blended with graphite anode material, provide near-term improvements with enhanced cycle stability, high silicon, and 100% silicon anodes represent the ultimate goal for many developers. Continued research and innovation in material design, demonstrating manufacturing capability and costs, as well as competition amongst and demand from end-users, will determine how quickly these technologies can be commercialized and integrated into mainstream battery applications.
IDTechEx’s new report, “Silicon Anode Battery Technologies and Markets 2025-2035: Players, Technologies, Applications, Markets, Forecasts”, provides analysis into the various silicon anode technologies and benchmarks the performance reported from various anode developers. Forecasts for the silicon anode market are provided by silicon technology (silicon-additive, mid-silicon, high-silicon), application (battery electric cars, commercial EVs, and electronic devices), and region (China, US, Europe, global).
To find out more about this report, including downloadable sample pages, please visit www.IDTechEx.com/SiliconAnode.
For the full portfolio of batteries and energy storage market research available from IDTechEx, please see www.IDTechEx.com/Research/ES.
About IDTechEx
IDTechEx provides trusted independent research on emerging technologies and their markets. Since 1999, we have been helping our clients to understand new technologies, their supply chains, market requirements, opportunities and forecasts. For more information, contact research@IDTechEx.com or visit www.IDTechEx.com.
