BATTERY TECH
New lithium-ion batteries use developments in nanotechnology to quintuple the voltage compared with ordinary batteries – and can considerably reduce the charging time for computers, smartphones, and electric cars.
Energy storage will be a crucial part of our transition to a green economy. Here are four new battery technologies which could help save the world.
American scientists from the Texas A&M University have invented a new technology that could lead to an upgrading of the lithium-ion batteries in our phones, laptops and electric cars. In short, the technology uses a scaffold of carbon nanotubes in the battery’s one electrode, enabling it to handle far higher voltages, also becoming much safer as a consequence.
An ordinary lithium-ion battery has an electrode at each end, between which lithium ions travel as the battery is charged and discharged. When the battery is charged, the ions settle on the negative electrode – the anode. When it is discharged, they settle on the positive electrode – the cathode. Currently anodes are made mostly of a mixture of graphite and copper, but an anode made of pure lithium would dramatically increase the energy density of the anode, and hence of the whole battery. It would increase battery capacity tenfold, and make charging much faster.
The problem with lithium anodes is that they often wear out too quickly. When lithium ions collect in the anode, they tend to lump together and produce dendrites – small crystalline structures that look like trees. Over time, these dendrites grow, and eventually the battery can leak, potentially causing a short circuit and at worst an explosion.
However, the Texan scientists have a solution that makes it possible to build a battery with a more stable lithium anode. By adding a porous 3D scaffold made of tiny nanotubes, the formation of dendrites can be reduced. The nanoscaffold is made of carbon that is partly lined with molecules and able to bind to lithium ions. The scaffold is located in a continuation of the anode, holding on to the lithium ions so they will not lump together on the surface of the anode. This ensures that no dendrites form, even though the scientists use energy-dense lithium for the anode. Overcoming the dendrite issue could improve battery capacity and charging speed without compromising the safety or durability of the battery.
The Texan scientists say that their best anode can hold on to a voltage five times higher than is possible with ordinary lithium-ion batteries. With such capacity, charging time could end up being only a fraction of the present level, which would be an especially crucial benefit for electric cars.