In 2010, Thackeray and Johnson were shocked by a report from Dalhousie University. Jeff Dahn, a professor at the university, is a battery researcher with a reputation. After applying for the NMC patent, 3M also applied for and obtained a patent for the NMC technology jointly developed by Dahn’s team and 3M. Dahn announced a major advance in the material’s performance. While doing the experiment, after he raised the voltage, the capacity of the battery suddenly increased.
If you inject lithium into a battery, you apply a voltage to the battery that moves the lithium from the cathode to the anode — the process of charging the battery — and the structure of the battery creates a strong resistance. It restricts the free flow of lithium, thereby limiting how fast energy can be extracted and how fast electric vehicles can be driven. Taking NMC as an example, this structure contains higher energy and can intercalate a large amount of lithium, but the power is relatively low, so it cannot be extracted quickly. Dahn’s solution was to charge the battery to more than 4.5 volts, or around 4.8 volts, which is a lot higher than the usual 4.3 volts. After the voltage rises, the electrons start to shuttle. The results were surprising. In theory, Dahn could get all the lithium moving between the two electrodes. It shouldn’t be possible to extract much lithium from the cathode, as that would tear down the important “walls” of the cathode’s lattice structure, collapsing the edifice of oxygen and metal atoms. However, Dahn found he could achieve his goals.
Johnson walked into the lab and tried to repeat Dahn’s claim with Li2MnO3. He raised the voltage above 4.5 volts. The result, as Dahn reports, was a sudden increase in the battery’s capacity.
This is an important discovery. The numbers confirm the veracity of the story. Typically, a lithium-ion battery like Goodenough’s lithium cobalt oxide can store 140 milliamp-hours of charge per gram. This capacity was innovative at the beginning of the invention of lithium-ion batteries, but it could not meet the needs of the new electric era. By cranking up the voltage, Johnson could get more charge — 250 mAh per gram, which is even higher than the 220 mAh Dahn reported on. Johnson tried again, bumping the capacity up to 280mAh, which is almost twice the performance of lithium cobalt oxide. These experiments show that this NMC is even more powerful, and much more powerful, than the version of NMC they originally created five years ago. Not only did Li2MnO3 immediately become the previously expected enhancer, but it became very solid and active at voltages above 4.5 volts. At this voltage condition, you can activate a completely new version of the NMC that is “on the market” for the first time. This is NMC version 2.0, the breakthrough technology that could push electric vehicles beyond the “hurdles” that challenge gasoline engines.
Argonne researchers were quick to publish their own findings. As for intellectual property (IP), they also take it into account — the voltage increase causes the battery capacity to increase, which is just a fresh understanding of the original patent application in 2000.
Aman and his team fought in the lab for another achievement. It involves an often overlooked part of the battery, the electrolyte that floods the cathode and anode. It is because of this liquid that ions can move from anode to cathode and from cathode to anode. However, there are times when the battery is overcharged and there is a risk of fire. The phenomenon has created a serious PR hazard for lithium-ion batteries and the products that use them – the number of incidents where laptops catch fire in airport lounges and consumers start to worry. Oman’s team invented and patented a new molecule based on boron and fluorine. Just a small amount of this molecule in powder form is added to the electrolyte, and it absorbs excess electrons, thus reducing the chance of a fire. Oman has become a full-fledged scientist in the NMC team. Several members of this team have successfully translated their scientific findings into a batch of patents centered on this NMC, which is arguably more valuable than any competitor’s latest battery development.