Liquid Metal Battery Corp is a MIT spinoff company led by professor Donald Sadoway. They're working on what they hope will be very cheap and very reliable batteries that are large enough to store many megawatt-hours of energy from the grid. This would help mitigate greatly the intermittency problem of renewable sources like wind and solar, and thus help make our grid cleaner. For more info about how liquid-metal batteries work, check out this post.
Before LMBC can get to large-scale commercial batteries, they must first scale things up and prove that they work. They already have working prototypes of various sizes, but nothing yet that can make a difference on the grid. Making these prototypes and testing them, and then making a factory to build the real deal costs a lot of money. That's why it's great news that the startup, which is already backed by Bill Gates and Total (cue conspiracy theorists) has raised a new round of financing of $15 million dollars, with Khosla Ventures being a main investor.
For more info, check out: Grid-Scale Metal Liquid Batteries Could Revolutionize Renewable Energy Use