Some hurdles remain to creating a production-grade battery, such as a tendency for the pack to shed a small amount of capacity whenever it's put under enough stress.
The United States and other Western nations have demanded that Iran stopped its uranium-enrichment program, which they perceive as a precursor to production of nuclear warhead-grade material.
The U.S. and its allies are seeking to gain Iran's willingness to suspend its production of near weapons-grade nuclear material at its uranium-enrichment sites in return for economic incentives.
They too want to reopen some of their closed mines to look for low-grade ore, and plan to expand production through joint ventures with international players.
At the talks in the Kazakh city of Almaty they are asking Tehran only to greatly limit its production and stockpiling of uranium enriched to 20 percent, which is just a technical step away from weapons-grade uranium.