Energy Technology Ventures, a General Electric-NRG Energy-ConocoPhillips joint venture, and Aster Capital, backed by European industrial groups Alstom, Schneider Electric and Rhodia, are two funds backing Ioxus, a US-based battery maker.

Ioxus, a US-based battery maker, has raised $21m in its series B round from a consortium including two tri-party corporate venturing funds.

Energy Technology Ventures, a $300m General Electric-NRG Energy-ConocoPhillips joint venture set up in January, and Aster Capital, backed by European industrial groups Alstom, Schneider Electric and Rhodia, were the two funds. The others in the consortium were Northwater Capital, through its Northwater Intellectual Property Fund, and venture capital firm Braemar Energy Ventures.

Kevin Skillern, venture capital leader…