The Next Source for EV?

The main source of Electric Vehicles is batteries, which provide the necessary energy to power the Vehicle's electric motor. The most common type of battery used is Lithium-ion (Li-ion) batteries, although other types such as solid-state batteries are being researched and developed for future use.

Let's have a look at the simple composition of Lithium-ion Batteries. Lithium-ion batteries consist of a cathode (positive electrode), an anode (negative electrode), and an electrolyte. Common materials used as cathodes are lithium cobalt oxide (LiCoO2), lithium iron phosphate (LiFePO4), and nickel manganese cobalt oxide (NMC). The anode is typically made of graphite. The electrolyte is a conductive solution that facilitates the movement of lithium ions between the cathode and anode during charging and discharging.

Abundant in Nature?

When it comes to abundant in nature, Lithium is not as abundant as elements like silicon or aluminum, it is widespread enough and can be economically extracted from various sources, including lithium-rich brine deposits and lithium-containing minerals.

Compared to the other cathode materials such as Cobalt and Nickel.

Cobalt is a more limited resource, and a significant portion of global cobalt production comes from a few countries. The industry is actively exploring ways to reduce or eliminate cobalt in battery formulations due to ethical and sustainability concerns associated with some cobalt mining practices.

Nickel is more abundant than cobalt, and there are efforts to increase the nickel content in batteries, as it allows for higher energy density. However, like cobalt, nickel extraction and processing raise environmental and ethical concerns, leading to increased attention to responsible sourcing.

A seemingly simple shift in lithium-ion battery manufacturing could pay big dividends, improving electric vehicles (EV) ability to store more energy per charge and to withstand more charging cycles, according to new research led by the Department of Energy's Pacific Northwest National Laboratory.

The nickel-rich battery vision

Cathodes for conventional EV batteries use a cocktail of metal oxides—lithium nickel manganese cobalt oxides (LiNi1/3Mn1/3Co1/3O2), abbreviated NMC. When more nickel is incorporated into a cathode, it greatly increases the battery's ability to store energy, and thus, the range of the EV. As a result, nickel-rich NMC (such as NMC811, where the "8" denotes 80% nickel, the first "1" denotes 10% cobalt, and the second "1" denotes 10% Manganese(8:1:1)) is of great interest and importance.

The most significant feature of the NMC 811 battery is its high energy density and reduced cost of EV Batteries. This comes from the Nickel in the cathode which can increase the material activity and thus the energy density. Additionally, the high Nickel content is important for increasing the capacity. The cobalt is also an active component that stabilizes the laminar structure of the material, thereby increasing the discharge capacity of the material. The manganese component, which plays a supporting role in the electrodes provides stability during charging and discharging.

However, high-nickel NMC cathodes formed using the standard method are agglomerated into polycrystal structures that are rough and lumpy. This meatball-like texture has its advantages over regular NMC. For NMC811 and beyond, though, the bulbous polycrystal fissures are prone to splitting apart, causing material failure. This renders batteries made using these nickel-rich cathodes susceptible to cracking, they also begin to produce gases and decay faster than cathodes with less nickel.

Challenges of synthesizing single-crystal NMC811

One strategy to fix this problem - convert that lumpy, polycrystal NMC into a smooth, single-crystal form by eliminating the problematic boundaries between the crystals—but this conversion is easier said than done. In laboratories, single crystals are grown in environments such as molten salts or hydrothermal reactions that produce smooth crystal surfaces. However, these environments are not practical for real-world cathode manufacturing, where lower-cost, solid-state methods are preferred.

In these more typical solid-state approaches, an NMC cathode is prepared by mixing a metal hydroxide precursor with a lithium salt, directly mixing and heating those hydroxides, and producing the agglomerated (lumpily clustered) polycrystal NMC. Using a multiple-step heating process results in micron-sized crystals, but they are still agglomerated, so the undesirable side effects persist.

Solution

Employ advanced synthesis techniques to produce high-quality single crystal or polycrystalline NMC 811 cathode material.
Improve the electrochemical performance of NMC 811 to enhance battery efficiency and longevity.
Develop cost-effective methods for synthesizing NMC 811 without compromising performance.
Facilitate the large-scale production of NMC 811 for commercial applications.
Create a resilient and sustainable supply chain for the raw materials used in NMC 811 production.

In conclusion, the development and widespread adoption of electric vehicles (EVs) heavily rely on advancements in battery technology, with Lithium-ion (Li-ion) batteries being the primary energy source for EVs. Understanding the composition of Li-ion batteries, particularly the cathode materials such as lithium cobalt oxide (LiCoO2), lithium iron phosphate (LiFePO4), and nickel manganese cobalt oxide (NMC), is crucial for enhancing their performance.

While lithium, a key component, is not as abundant as some other elements, its extraction remains economically viable from various sources. However, the industry faces challenges associated with environmental and ethical concerns related to the extraction of materials like cobalt and nickel.

The research spotlight has shifted toward nickel-rich NMC cathodes, such as NMC811, which boasts an 80% nickel composition. This shift aims to improve energy density, extend the range of EVs, and reduce costs. The high nickel content enhances material activity and increases capacity, while cobalt stabilizes the material's structure. However, challenges arise in synthesizing single-crystal NMC811 due to the current polycrystalline structures being prone to splitting and material failure.

Addressing these challenges requires advanced synthesis techniques to produce high-quality single-crystal or polycrystalline NMC811 cathode material. Additionally, efforts should focus on improving electrochemical performance, developing cost-effective synthesis methods, and facilitating large-scale production for commercial applications. It is equally important to establish a resilient and sustainable supply chain for raw materials, considering the environmental and ethical concerns associated with their extraction.

By tackling these aspects, the electric vehicle industry can enhance the efficiency, longevity, and overall sustainability of Li-ion batteries, contributing to the broader goal of transitioning to cleaner and more sustainable transportation solutions