However, please keep in mind that the landscape of battery technology evolves rapidly, so the status and developments of these companies may have changed since then. Here are some notable companies and institutions that were working on graphene battery technologies:

1. Nanotech Energy: Nanotech Energy is a U.S.-based company that has focused on developing graphene-based energy storage solutions, including batteries and supercapacitors.
2. StoreDot: StoreDot, an Israeli company, was known for its work on fast-charging batteries and claimed to have developed graphene-infused battery graphene battery companies technologies that could charge electric vehicles rapidly.
3. ZapGo: ZapGo, a UK-based company, specializes in graphene supercapacitors and was working to replace traditional lithium-ion batteries with graphene-based supercapacitors for faster charging and longer lifespan.
4. Graphenano: A Spanish company, Graphenano, had been working on graphene batteries and had made claims about the development of a graphene polymer battery with potential applications in electric vehicles and energy storage.
5. Vorbeck Materials: Vorbeck Materials, based in the United States, had been involved in the development of graphene-based conductive inks and composites for various applications, including batteries.
6. Samsung: Samsung, a major electronics manufacturer, had been conducting research and development on graphene-enhanced batteries to improve the performance of their devices.
7. Academic and Research Institutions: Numerous universities and research centers around the world were actively engaged in graphene battery research. These institutions often collaborate with industry partners to advance the development of graphene-based batteries and related technologies.

Remember that the information provided is based on the state of the industry as of September 2021. Battery technology is an area of rapid advancement, and new companies and developments may have emerged since that time. I recommend checking the latest news and industry reports for the most up-to-date information on graphene battery companies and their products.