This "breakthrough" is now 7 years old, and still my favorite. From
http://www.greencarcongress.com/2011/09/alginate-20110909.html
" In a paper published in the journal
Science, the team reported mixing silicon nanopowder with alginate to yield a stable battery anode possessing reversible capacity 8 times higher than that of the state of the art graphitic anodes. The anode also demonstrates a coulombic efficiency approaching 100% and has been operated through more than 1,000 charge-discharge cycles without failure."
Seems to hit all the high points with cheap to produce, environmentally friendly process, compatible with common battery manufacturing process. The down side seems to be "The electrodes showed a moderate rate capability, the team found, inferior to that achieved in Si-C composite anodes with hierarchical porosity or in nanowires." Although that seems to be still high at 4200mA/g. No news in 7 years, does anybody know what happened?