Driving the Future
Over the next year or two, many electric cars and plug-in hybrids are scheduled to come to market. Just to name a few: The Nissan LEAF, Chevy Volt, Electric Ford Focus, Tesla Model S, Fisker Karma, Pininfarina/Bolloré Bluecar, and Mitsubishi i MiEV. Early adopters will probably eat them up, and their electric range will no doubt be enough for people who rarely drive long distances (and many have a second vehicle, or could rent or borrow). But to truly make EVs mainstream and replace the internal combustion engine, further technological innovations will be required to make batteries store more power, cost less to manufacture, and recharge faster. Let's look at a few recent breakthroughs to see what the electric car of the future might run on.
Silicon Nanotube Battery Anodes...
Researchers from Stanford University and Hanyang University in Ansan, South-Korea, in collaboration with LG Chem (makers of the Chevy Volt battery), have made a breakthrough that could change the future of electric cars. They have shown that by replacing the conventional graphite electrodes in lithium-ion batteries with silicon nanotube electrodes (silicon nanotubes, not the more common carbon nanotubes), 10 times more charge could be stored. This could not only greatly extend the range of electric cars, but it would also make gasoline-electric hybrids more efficient by allowing them to run in electric mode for longer periods.
Initially, they were having problems finding a high-performance anode to pair it with this cathode, but thanks to another recent breakthrough (below), this might not be a problem anymore.
More details: Li-Ion Battery Breakthrough: Silicon Nanotubes Boost Capacity 10x
Image: ACS, Yang et al.
...and Lithium-Sulfur Cathodes
To go with the anode mentioned above, researchers created a new lithium sulfide (Li2S) cathode:
By combining the new cathode with the previously developed silicon anode, the team created a battery with an initial discharge of 630 watt-hours per kilogram of active ingredients. This represents an approximately 80 percent increase in the energy density over commercially available lithium-ion batteries, according to Stanford's Cui, who was a coauthor of a paper describing the work published last month in Nano Letters. Further increases in energy density--as much as four times that of lithium-ion batteries--are theoretically achievable by optimizing the battery's electrodes, Cui says. (source)
More details: Lithium-Sulfur Breakthrough Could Mean Safer and More Energy-Dense Batteries
Ordinary Paper + Ink + Nanotubes = Battery
Stanford researchers have discovered a way to rapidly make batteries and supercapacitors with ink that contains carbon nanotubes and ordinary paper. As shown in the video here, they simply coat the paper with the special ink, put it in an oven and out comes a highly conductive storage device.
"The small diameter helps the nanomaterial ink stick strongly to the fibrous paper, making the battery and supercapacitor very durable. The paper supercapacitor may last through 40,000 charge-discharge cycles - at least an order of magnitude more than lithium batteries."
More details: Breakthrough? Ordinary Paper + Ink + Nanotubes = Battery