Keywords: ALD, atomic layer deposition, Li-ion, coatings
Summary:From improving performance of lithium-ion batteries, fuel cells, and supercapacitors, as well as enabling new materials synthesis techniques, ALD has proven to be a vital technology for meeting the growing demands of mobile and stationary power applications. As a result of the realized benefit ALD imparts to lithium-ion battery technology in-particular, numerous industrial entities are pursuing ALD for product integration. Unfortunately there is wide spread confusion about the specific benefits and the most effective methods for applying ALD, which has stunted the overall advancement of ALD-enabled technologies. Here, we will discuss ALD methodologies and best-suited applications in an effort to clarify the most appropriate steps towards an ALD-enhanced energy storage future. As it pertains to secondary battery technology there exists two distinct realms of ALD, particle coating and electrode coating. Both have advantages and disadvantages that make them more or less appropriate for a desired performance improvement or application. It is critical for anyone considering ALD- enhancement of their technology to know the strengths and weaknesses of both technologies so that they can pursue the most appropriate method. Typically the final denominator in the decision making process is cost, and while that cost value may appear simple if your calculation produces a red number or a black number, arriving at that number requires a significant amount of technological input. In the case of ALD, the final battery product must have a justifiably lower cost per energy unit per charge/discharge cycle, or $/Wh/cycle. In order to arrive at that number consideration must be given to the following three stages of ALD development: 1. Initial R&D - Determining the optimal ALD method and/or chemistry 2. Capital Cost - Implementing the R&D optimized ALD process into a battery production line 3. Pack Performance - ALD-enabled battery performance comparison to its base competitor battery Much of the confusion around whether ALD on particles (ALDP) or ALD on Electrodes (ALDE) is ‘better’ is speculated to stem from the lack of scalable production methods for ALDP. Until recently, ALDP has been performed in fluidized beds that are slow and expensive to operate and which cannot be scaled. With the invention of the Semi-continuous ALD system, pricing for ALDP can be considerably reduced which leads to new considerations when comparing ALDP and ALDE. In this particular scenario ALDP has become the best avenue as it lends more readily to the production of commercial scale quantities of material thanks to the new semi-continuous production method. This is just one of many differences in understanding that has spawned confusion around ALD in recent years. This talk aims to clarify the $/Wh/cycle reality and provide a basis for pursuing the most viable paths towards technological integration of ALD.