NanoGraf has been working for some time on a new material for silicon based anode, high energy density, which has the potential to replace graphite-based anodes in current lithium-ion batteries in the long term. The result is usable in a wide variety of applications, from consumer electronics to electric vehicles. Now, the American company based in Chicago announces an important advance in this technology, having achieved the highest energy density in the world with its cylindrical 18650 cells.
The announcement of the American company affirms that its new cylindrical 18650 cells (18 mm in diameter and 65 mm high) surpass the rest of those offered by the battery industry with this format since they offer 810 Wh/l when subjected to an electrical load of 4 Ah. The ampere-hour represents the amount of electricity that, in one hour, passes through a conductor through which a direct current of 1 A circulates. It is used to evaluate the capacity of a battery as the amount of electricity that it can store during charging and return during download.
In 2019, the US Automotive Research Council, a consortium of Ford, General Motors and Stellantis, provided NanoGraf with $7.5 million for a 36-year electric vehicle battery research and development project. months.
In 2021, NanoGraf announced that it had developed a 3.8 Ah cylindrical lithium-ion cell, also in 18650 format, which already reached 800Wh/l, which means that this latest version reflects a small improvement. In its statement, the company assures that “the greater stability and highly scalable nature of its new silicon anode cell solves the weaknesses of the first generation commercial SiOx anodes and has shown that it is ready to be implemented in cell designs. existing cells maintaining the same production processes”.
Silicon is already widely used in microprocessors and photovoltaic power systems, as it is a material that can hold up to 10 times more energy when used as an anode than the graphite it replaces. Therefore, solving the swelling process can help scientists make them viable for electric vehicles.
A silicon anode battery is actually a type of lithium-ion battery in which the graphite that forms the microstructure of the anode is replaced by silicon nanotubes or a coating of this material. While it has been shown to provide multiple advantages over ordinary lithium graphite anodes, there is a drawback of swelling, which needs to be addressed. This occurs because lithium ions penetrate the anode in such a way that they displace the silicon atoms, creating a “lithium squeeze” and causing it to swell up to three or four times its original size.
Solving this problem, silicon allows long life and high energy storage, resulting in a considerably longer battery life. NanoGraf claims that its “silicon anode 18650 cells represent a step forward in establishing a domestic battery supply chain.” Biden’s Reduce Inflation Act supports installation of key battery components in the US Francis Wang, CEO of NanoGraf says this is “a historic opportunity for technological innovation for NanoGraf products.
