Wireless power. It’s less sci-fi sounding than it once was, thanks to induction charging like that based on the Qi standard, but that’s still a tech that essentially requires contact, if not incredibly close proximity. Magnetic resonance is another means to achieve wireless power, and perfect for much higher-demand applications, like charging cars. But there’s been very little work done in terms of building a solution that can power your everyday devices in a way that doesn’t require thought or changing the way we use our devices dramatically. Check out also Wireless Devices that Need no Battery.