from kurzweilai.net
New microbatteries developed by researchers at the University of Illinois at Urbana-Champaign, out-power even the best supercapacitors and could drive new applications in radio communications and compact electronics.
http://www.kurzweilai.net/new-microbatteries-a-boost-for-electronics
http://news.illinois.edu/news/13/0416microbatteries_WilliamKing.html
another interesting link:
http://braungroup.beckman.illinois.edu/Lange_Jonathan_Thesis.pdf