Low-cost, solvent-free manufacturing of ultra-high-performance electrodes that can handle high loads and have high performances
Due to the increased energy requirements for different working scenarios, research is being conducted in order to develop high-capacity electrode materials. For instance, hybrid electric vehicles have a typical requirement of 2 mAhcm-2. Electric vehicles require 4 mAhcm-2. The use of thicker lithium-ion electrodes offers a potential increase in energy density. However, this also poses several challenges to electrode performance. Once the electrode thickness has reached the critical thickness, it will start to crack. The capillary force formed by particles suspended at the air/solvent interface is believed to cause this cracking. Cracks like these can be a major quality issue during electrode manufacture.
Yan Wang and Heng Pa from Texas A&M University and Worcester Polytechnic Institute have developed an innovative method to produce ultra-high loading NMC811 and Graphite electrodes. The electrodes were significantly better than those prepared using traditional slurry forming. The microstructure optimized of the dry printed (DP) electrolyte enhances the electrolyte permeability. It also reduces diffusion tortuosity in lithium-ion, thereby improving performance. This new electrode production method also allows for a uniformer growth of CEI and SEI. The result is a doubled cycle life when using DP electrodes in soft-packs with DP electrodes. Aside from the improvement in performance, the method has also shown a substantial overall cost benefit of 29.2%. This could potentially revolutionize battery manufacturing. This research highlights the high capacity of advanced battery manufacturing technologies that are solvent free.
Conclusion
Summary: This research explores DP electrodes manufactured with solvent-free production technologies. This new approach reduces the electrode tortuosity (from 2.21 to 2.63 in cathode for example, and from 3.53 to 3.63 on anode), and thus improves rate performance.
Optimising the distribution of carbon-binders can result in high energy density batteries. This allows for high-energy batteries to be produced without impacting their performance. In addition to providing a layer of protection, the rational placement of carbon binder sites on the AM surface particles provides an additional protective layer. Not only does this stabilize surface side reactions, it also stimulates CEI and SEI. In battery operation this reduces electrolyte and lithium decomposition, which increases the life of batteries. A solvent-free battery approach not only enhances electrochemical and physical property of the batteries, but it also offers obvious economic as well as environmental benefits. This reduces capital expenditure, the demand for manpower, and infrastructure. That is the most remarkable thing about this technology. It reduces energy usage in the manufacturing of electrodes by 95.5%. From $105.5 million down to $4.75 million. In terms of cost, it is estimated that the use of solvent-free technology for the electrode production process will save $5.33 on each kWh. That is equivalent to an 5.13% decrease in the cost per battery layer.
The low-cost high-efficiency electrode manufacturing technology can be used to unlock fast charging capabilities and stable cycling abilities of ultra high loading electrodes. Batteries will have a high energy density with impressive high-rate performances and a longer service life.
