Li-ion batteries will last 10 times longer and will charge in a tenth of the usual time

Processing power of today's smart phones and their ability to perform multiple functions are truly amazing. However, a general problem of these devices is the battery life that feeds them. They don't even come close to the performance these smartphones.

This is why many of us need to carry around an additional MP3 player, or, as we go by car, a GPS, although the smartphone meets with success of these functions and more.

Now, a new technology created by researchers at Northwestern University, USA, is about to change that. Engineers have made ​​an electrode for lithium-ion batteries - the rechargeable batteries used for most electronic devices - which could provide gadgets an operating range of ten times longer and duration of recharge from outlet ten times faster than normal.

According to statements of Harold H. Kung, coordinator of the project, even after 150 charges, the new type of battery will still be five times more effective than lithium-ion batteries on the market today. Promise of American engineers would translate to more than a week of autonomy and a 15 minute full recharge any battery.

Today's batteries are charged through a chemical reaction manifested by lithium ions circulating back and forth between the two ends of the battery, the anode and cathode. When the battery is fully charged and used, the ions travel from the anode through the electrolyte, and reach the cathode. By the time all ions are in the cathode, the battery is low. And when charging, the process is reversed and the ions move from cathode towards the anode.

The proposed electrode combines two chemical processes to remove the two major shortcomings of the Li-ion battery technology: their limited ability to store energy (number of ions stored) and relatively slow charging rate (speed of movement of lithium ions during charging). The electrode eliminates these problems and promises super-batteries for next generation devices.

In the current version, anode - made ​​of thin layers of graphene - can store only one lithium atom for every six carbon atoms. Experienced engineers replaced carbon with silicon, which can handle much more lithium (four lithium atoms to a silicon atom) than carbon. The problem is that silicon expands and contracts during the charging cycle. This soon leads to a loss of ability to recharge the battery.

But the team from Northwestern University solved this difficulty by stabilizing the silicon. Engineers have made ​​this possible by setting silicon between graphene layers, like a sandwich. This maximizes the amount of ions that can cross layers, maintaining flexibility so that the battery assembly is not subject to pressure during charging.


The second problem solved by Kung's team was charging time. This was achieved by creating microscopic holes (10-20 nm) in the graphene layers. They allow ions to move the second and shorter route to the anode, which reduces the load at a fraction of the usual.


Extrapolating the implications of increased autonomy of the batteries for our gadgets, new electrode may contribute to decreasing size batteries for electric cars and a longer life. The technology could be commercially available anytime between three and five years from now.