The most important advances in materials this year could make cleaner vehicles and renewable electricity more affordable.

The best bet for low-cost electric-car batteries may be Tesla Motors’ “gigafactory,” which the car maker started constructing this summer in Nevada. The factory will use sheer scale to drive down the cost of batteries with fairly conventional lithium-ion chemistry—plans call for its annual production of lithium-ion batteries to match that of all other worldwide producers combined. However, radical changes in battery chemistry—solid-state batteries, and liquid batteries you can recharge in minutes by pumping in new electrode materials—also made encouraging progress this year.

Inexpensive batteries could also help overcome the key problem with renewable sources of electricity like solar and wind: their intermittency. Low-cost batteries that use the sodium ions from seawater as their electrolyte hit the market this year, promising to enable round-the-clock solar power by storing surplus energy during the day. Batteries made from other cheap materials—such as iron or the organic compounds found in rhubarb—could lead to massive-scale energy storage, letting whole cities run on solar power through the night.

Solar power generally remains more expensive than electricity generated from fossil fuels, but improvements in conventional silicon cells (which are being baked into plans for a solar “gigafactory”) are still driving costs down. And eventually, breakthroughs in ultra-efficient solar cells made from semiconductor materials other than silicon could make solar power by far the cheapest source of electricity.

Other materials advances this year could augment human abilities and restore function to people who’ve been injured. Researchers reached a milestone with artificial skin that could give prosthetics a realistic sense of touch. An electronic skin patch can detect Parkinson’s-like tremors and automatically deliver medicine. Powerful, reversible adhesives inspired by gecko toes allowed a human to scale a glass wall. Google revealed an ambitious project to create multifunctional contact lenses that can adjust their focus and monitor glucose levels; we took a look at what else might be done with contacts.

In a separate project, Google launched an effort to make nanoparticles that can detect traces of cancer or heart disease. There are plenty of challenges, but this year some other researchers made a significant advance toward this goal, demonstrating that nanoparticles can find the deadliest cancer cells in blood.

Researchers showed they could use a 3-D printer to make blood vessels, overcoming a major hurdle to growing complete human organs that could serve as replacements in sick people.

Perhaps the most fascinating materials advance of the year has no clear application yet: it’s a durable nanostructured ceramic that’s one of the strongest and lightest substances ever made.