Researchers have long wanted to use silicon in batteries because of its cheapness and availability, as well as its high potential capacity, but repeated swelling and shrinking when used in batteries wears out the tiny silicon plates, quickly rendering them useless.
Zhou and his team first experimented with porous nanowires, which are less than 100 nanometers in diameter and only a few microns long. The pores allowed the silicon to change in size without destroying the material, and also increased the anode's surface area, allowing ions to move more quickly through it.
The problem lies in the nanowires, which are hard to manufacture in large amounts, so the team switched to commercially-available nanoparticles. Researchers etched the same pores onto their surfaces, and while the original nanowire design could last up to 2,000 recharge cycles, as reported in the journal Nano Lett last year, the particles were less effective.
This procedure can be used on anything from a car battery to a mobile phone, the latter of which can have implications for more powerful smartphones that won't die with continuous use.
The battery is under a provisional patent now, but could be available commercially within two to three years. Zhou is working to improve the design to extend the battery's life — the silicon anode lasts about 200 recharge cycles, compared to 500 in graphite-anode batteries. The team is also working to find materials for the cathode (the point where electricity flows out) that would work well with silicon.
Zhou's work was published in Nano Research in January.
