Disposing a Major Hiccup from the EV Sector’s Journey to Get Wider Acceptance

One can define a human society in more ways than they can even imagine, and yet none will do as good of a job as to when they mention that society’s tendency to constantly expand and become better over time. We say this because the stated tendency has already fetched the world some huge milestones, with technology emerging as quite a major member of the group. The reason why we hold technology in such a high regard is, by and large, predicated upon its skill-set, which guided us towards a reality that nobody could have ever imagined otherwise. Nevertheless, if we look beyond the surface for one hot second, it will become abundantly clear how the whole runner was also very much inspired from the way we applied those skills across a real world environment. The latter component, in fact, did a lot to give the creation a spectrum-wide presence, and as a result, initiated a full-blown tech revolution. Of course, the next thing this revolution did was to scale up the human experience through some outright unique avenues, but even after achieving a feat so notable, technology will somehow continue to bring forth the right goods. The same has turned more and more evident in recent times, and assuming one new discovery ends up with the desired impact, it will only put that trend on a higher pedestal moving forward.

The researching team at Pacific Northwest National Laboratory, in collaboration with Albemarle Corporation, has successfully developed a new approach for synthesizing single-crystal, high-energy, nickel-rich cathodes to give electric vehicles a greater amount of energy per charge. You see, cathodes, when brought into the context of typical EV batteries, rely upon a mix of metal oxides i.e. lithium nickel manganese cobalt oxides (LiNi1/3Mn1/3Co1/3O2), more popularly known as NMC. Now, upon enhancing the proposition of nickel in a battery, one is likely to notice that it would significantly aid the battery’s ability to store energy. However, having said so, high-nickel NMC cathodes formed using the standard methods are agglomerated into polycrystal structures that are rough and lumpy. This means, in simple terms, that batteries manufactured in such a way are more prone to splitting apart and cause material failure. Apart from their vulnerability to cracking, these batteries also tend to produce certain gases and decay faster than cathodes with less nickel. Now, researchers have previously tried to solve the given problem by converting the lumpy, polycrystal NMC into a smooth and single-crystal form, doing it with the elimination of problematic boundaries between crystals, but they all ended up running into a similar problem. While the proposed technique to facilitate the conversion was concerned with growing single crystal in environments containing molten salts or hydrothermal reactions, it was discovered that such an approach wasn’t exactly feasible for wider use. We say so mainly because of high costs. Hence, more like an alternative, following experiments would use cheaper solid-state methods where they mixed a metal hydroxide precursor with lithium salt, directly mixing and heating those hydroxides to produce polycrystal NMC.  However, as pocket-friendly as these methods might be, they couldn’t move past the point of delivering agglomerated, and therefore, lumpy structures. Talk about how the development in question solved that conundrum, the researchers involved introduced a pre-heating step that changes the structure and chemical properties of the transition metal hydroxide. In practice, when the pre-heated transition metal hydroxide reacted with lithium salt to form the cathode, it created a uniform single-crystal NMC structure which turned out to as smooth, even under magnification.

“This is an important breakthrough that will allow the highest energy density lithium batteries to be used without degradation,” said Stan Whittingham, a Nobel Laureate and distinguished professor of chemistry at Binghamton University. “In addition, this breakthrough on long-lived batteries will be critical to their use in vehicles that can be tethered to the grid to make it more resilient and to support clean renewable energy sources.”

The team has already conceived a prototype battery which came decked up with scaled single crystals. Going by the available details, this battery proved itself to be stable throughout what were 1,000 charge and discharge cycles. Furthermore, a look at the microscopic structure of the crystals after 1,000 cycles gave away no defects whatsoever. Complementing this technological prowess is the fact that cathode manufacturers can use their existing production facilities to conveniently produce single-crystal NMC811, and the same also goes for cathodes carrying more than 80% of nickel content.

“This is a fundamentally new direction for large scale production of single crystal cathode materials,” said Jie Xiao, the principal investigator of the project. “This work is only part of the cathode technology we are developing at PNNL. In collaboration with Albemarle, we are addressing the scientific challenges in synthesis and scale-up of single crystals and reducing the manufacturing cost starting from raw materials.”

At present, the researchers are scaling up this single-crystal NMC811 to kilogram level by using lithium salt provided by Albemarle. As for the future, though, they plan to begin a new research phase for their latest brainchild. All through the said phase, they will work alongside industry and university partners to conduct commercial-scale synthesis and testing. Surely, the details about this upcoming effort are scarce, but a certainty here is that the team will use conventional manufacturing equipment and techniques which have been industrially adapted. Such a decision ensures they avoid any potential disruptions that might come out of deploying an entirely new setup.

“During single-crystal synthesis at the kilograms level, we have identified a brand new world full of science and engineering challenges and opportunities,” said Xiao. “We are excited to apply this new knowledge to accelerate the commercial-scale manufacturing process.”

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