Some considerations about fast charging, and Storedot

Original post at Twitter here, in response to this post regarding StoreDot's announcement of a 4680-format cell.

I can think of one commercial battery with faster charging, Toshiba SCiB: 26 Ah cell w/ 0-80% in 6 minutes, thanks to the LTO anode (with drawback of lower energy density). Storedot approach is interesting but I imagine comes with some challenges…

Main obstacle to fast charging typically is graphite anode, and risk of Li plating (with risk made worse by the usually somewhat high thickness of the electrode). Thinner anodes with working potential further away from Li metal mean possibility for faster charging.

LTO is far from Li metal (1.55 V vs ~0.1-0.2 V for Gr) though not thinner for same capacity. So for high power you have to make both electrodes thin, and energy density suffers badly (SCiB is 106 Wh/kg according to spec sheet).

Storedot is working with Si and other anodes - high specific capacity, so can be v. thin but still high mAh/cm2. With v small particles, transport limitations at anode probably not an issue anymore.

SEM image of a Storedot silicon electrode cross-section, from

Would also mean that fast charge becomes accessible without having to sacrifice energy density that much, and in a bigger cell like a 4680 it could potentially be something that is attractive for EVs.

What I’d be curious about is 1. what is cycle life like in these cells, since nanoparticles + fast charging is generally a recipe for degradation, and 2. can heat generation during fast charge be managed on system level (and how does that affect cycle life).

I am sure we will see more of this coming up. Both Si anodes and solid state (in principle) offer routes to removing graphite-related fast charge limitations but will bring new problems to solve.

comments powered by Disqus