Higher capacity, faster charging times and a longer service life of batteries
Battery manufacturers and large buyers such as the automotive industry strive for higher capacity, faster charging times and a longer service life of batteries. Scientific tests have shown that spatial ALD can play a decisive role in this. SALD has been approached by large battery producers with the request to work this out in practice. To realize this, a research program has been started, in which SALD works closely with renowned research institutes including The Netherlands Organisation for Applied Sciences.
TNO research shows potential
Experts from TNO – one of Europe’s largest Research & Technology Organizations – are working on a revolutionary type of battery based on 3D technology and solid state. These batteries are intrinsically safe, light in weight, charge super fast and have a long service life. In the long term, these form the ideal solution for electric vehicles.
Spatial ALD is used to cover the solid state batteries with layers of functional material. This creates a 3D construction with a large surface. The ions now only have to travel a short distance, making charging and discharging much faster. The first applications can be expected in wearables, in which “wet” lithium batteries are still dominant. Solid state has the advantage that the battery cannot catch fire or explode.
Electric cars can travel three times as long with the intended safe and compact battery, while charging is five times faster. Moreover, the battery contributes to a clean world. See also the TNO website about this.
Spatial ALD improves Li-ion Batteries
Li-ion batteries are indispensable for consumer electronics and electric vehicles, and it is vital that the safety, longevity and capacity of these batteries is maximized. Spatial ALD can assist in this. For common Li-ion batteries that comprise liquid electrolytes, ALD can be used to prepare the solid-electrolyte interphase (SEI). This artificial SEI – typically about a nanometer in thickness – protects the anode or cathode active materials (CAMs) from the electrolyte, enhancing the long-term stability and safety of the Li-ion battery.
How it works – fundamental mechanisms
Promising cathode active materials (CAMs) in terms of capacity and cost are amongst others the Lithium Nickel Cobalt Manganese Oxide LiNiCoMnO2 (NCM) materials. The more Ni, the higher the potential capacity of the battery. However, when the Ni content increases, the battery becomes increasingly unstable and the cycle life is reduced, as the NCM surface is unstable in contact with the electrolyte. Detrimental Ni leaching and surface degradation occur. Additionally, the NMC material, that in layered form can store Li, undergoes phase changes and becomes unusable. Micro-cracking ensure new, fresh NMC materials keeps being exposed to the electrolyte, causing further deterioration of the battery. Similar problems arise at the electrolyte interface with other cathode and anode materials as well, such as spinel LiMnNiO2 (LMNO), LiMn2O4 (LMO) or LiCoO2 (LCO). The solution: use a thin chemically stable layer prepared by ALD to protect the anode or cathode active material.