A Major Constituent of Brown Algae for Use in High-Capacity Li-Ion Batteries



Identifying similarities in the material requirements for applications of interest and those of living organisms provides opportunities to use renewable natural resources to develop better materials and design better devices. Here, we harness this strategy to build high-capacity Si nanopowder–based Li-ion batteries with improved performance characteristics. Si offers more than an order of magnitude higher capacity than graphite, but exhibits dramatic volume changes during electrochemical alloying and de-alloying with Li, which typically leads to rapid anode degradation. We show that mixing Si nanopowder with alginate, a natural polysaccharide extracted from brown algae, yields a stable battery anode possessing reversible capacity 8 times higher than that of the state-of-the-art graphitic anodes.