Silicon Series (Pt. 1)
Our deep dive into the companies that work with silicon (Part 1)
This article is part of Intercalation Station’s exclusive paid series where we dive deeper into battery companies and the technologies they’re working on. Reach out for any inquiries, and thanks for being a supporter!
🚀 The silicon anode startup space is crowded
If you’re overwhelmed by the number of companies working with silicon and have trouble keeping track, we’re here to help. In this exclusive series for our supporters, we’re putting together a library of silicon anode companies and delineating what each one is doing differently with their flavor of silicon.
We’ll do this by looking at the publicly available information, patent portfolios, recent job postings, and expert interviews. Since there are so many companies in this space, we’re breaking things up into multiple issues.
In this first issue, we’re looking at Advano, Amprius, and Enevate. We’ll dig into the rest of the major players and start forming a larger silicon startup map in the following issues.
⚛️ Why do we care about silicon?
In two words: energy density. Silicon-based materials can significantly improve energy density compared to incumbent graphite. One silicon atom can hold four lithium atoms, where graphite needs six carbon atoms to hold just one lithium atom. This means silicon has a theoretical capacity of a whopping 3600 mAh/g compared to graphite’s 372 mAh/g.
This improved energy density doesn’t come without drawbacks. Silicon’s main weakness is its large volumetric expansion (300-400%) between Li alloying and dealloying during cycling. This can cause solid electrolyte interphase (SEI) development through excess silicon exposure and can eventually disintegrate the whole anode. As a result, it has been challenging to make long-lasting commercial cells with silicon dominant anodes. Today, only a sprinkle of silicon (3-8%) is generally used as an additive in graphite-based anodes.
❓The questions we’re looking into for each company
Materials: What are their key materials and components involved?
Formulation: What percent of their anode is silicon?
Volumetric Expansion: What is their strategy to accommodate silicon’s large volume change?
Stage: How far along are they in development?
Total Funding: How much funding have they raised?