Found a way to increase the capacity of lithium-ion batteries by 10 times

Around the world, dozens of scientific groups are looking for options to significantly increase the capacity of lithium-ion batteries. The introduction of silicon into the structure is considered a promising direction, but its fragility, fragility of compounds based on it and other problems did not allow this for a long time.

But it looks like scientists in Japan have managed to find a solution to the silicon problem. They came up with a new design of the anode, made of nano-sized silicon arcs, which give the necessary strength and durability.

Modern lithium-ion batteries and their disadvantages

So, to begin with, just a few words about how lithium-ion batteries work. So, as you know, a battery consists of a pair of electrodes (cathode and anode) and an electrolytic solution. So the main task of the electrolyte is the transfer of lithium ions between the cathode and the anode, which is just made of graphite.

So, during battery charging, lithium ions move along the cathode-solution-anode path. In the process of discharging, the movement of ions occurs in the opposite direction.

This design has proven itself well and has worked for more than a dozen years. But the main drawback of this whole debugged design lies in the fact that six carbon atoms must be used at once in the graphite anode to store one lithium ion. For this reason, these batteries have a low energy density.

Silicon and its uses

Nevertheless, if we look at such a material as silicon, then one of its atoms is able to bind with four lithium ions at once, which gives an almost 10-fold increase in energy density. Everything seems to be fine, but scientists still have not been able to stabilize silicon.

Since it is prone to significant expansion (up to 400% of the original volume), contractions and breaking during battery operation, then all these deformation effects destroyed the silicon anodes fast enough.

A research team from the Okinawa Institute of Graduate Technology and Technology (OSIT) proposed their solution to the problem of stabilizing the silicon anode. Engineers conducted a whole range of experiments with layers of silicon of various thicknesses in search of a golden mean, in which the conditions of high energy density and battery stability will be met.

Scientists have found that as the silicon layer increases, first there is an increase in stiffness, and after a certain point, there is a sharp decrease. It was decided to study in more detail the reason for such a transition, and this is what scientists have been able to establish.

It turned out that when silicon is deposited on metallic nanoparticles, tiny pillars in the form of inverted cones begin to form, thickening towards the top.

It turns out that with the deposition of an increasing number of silicon atoms and, accordingly, the growth of the pillars, they become so wide that they touch each other and thus form an arched structure of a nanometer scale.

Such a structure is quite strong and even used by humans in construction. And it turns out that before these nano arches were formed, the structure is rather weak, and their even greater growth creates a spongy structure with holes, which is not so effective.

And only at the moment of the formation of such arches, a balance is created, which makes it possible to provide an increased charge capacity and is able to withstand a large number of charge / discharge cycles.

It is not yet known when the new lithium-ion batteries with a silicon anode will go on sale, but the fact that this direction is promising can be recognized already at this stage.

Did you like the material? Then put your finger up and subscribe to the channel. Thank you for your attention!