This key field is experiencing rapid development with many approaches, so only the occassional significant breakthrough will be posted as time allows.
There have been results by John Bedini and others (see Home page) that demonstrate non-galvanic battery power using only a mixture of salts and and lead or two dissimilar metals - no liquid! Also John Hutchinson has used only dry rocks with metal! This has not been in the mainstream of research to date. In addition, see the documented work of T. Henry Moray in the document Lost Science: Gerry Vassilatos on the Unified Field Technology Research - Resources page.