Enhancing Nanostructured Nickel-Rich Lithium-Ion Battery Cathodes via Surface Stabilization

NU 2020-195

INVENTORS
Norman Luu
Jin-Myoung Lim
Mark Hersam*

ABSTRACT
Lithium-ion battery cathodes based on layered transition metal oxides have emerged as ideal candidates for high-power technologies such as drones, power tools,and electric vehicles. These applications require batteries that can deliver high power while maintaining low impedance and long cycle life. Electrodes based on nanoparticle cathode materials are an attractive option for accomplishing this goal, since the reduced surface-area-to-volume ratio implies greater charge transfer sites and shorter solid-state lithium-ion diffusion lengths. However, at nanoparticle length scales, active material surface instabilities become increasingly detrimental to electrochemical performance. For example, surface impurity species remaining from materials synthesis and electrolyte degradation compounds formed in-operando at the cathode-electrolyte interface limit the achievable capacity, increase impedance, and decrease long-term cycle life. To address these issues, we have developed an annealing procedure to remove these surface impurity species in addition to a subsequent conformal graphene coating scheme to comprehensively enhance cell performance for Ni-rich cathodes (e.g., LiNi0.8Co0.15Al0.05O2, or NCA). Furthermore, our conductive graphene network can completely replace traditional carbon black additives, which results in a substantial increase in the electrode volumetric capacity. Overall, this work demonstrates a facile and scalable pathway to achieve high-power, long-lasting nickel-rich nanoparticle cathodes for lithium-ion batteries.

APPLICATIONS  

• Li-ion batteries
• Graphene coating or graphene encapsulation
• Cathode materials
• High power/high energy density electrode
• Conductive additive in electrode
• Intercalation materials

ADVANTAGES  

• Quick, low-temperature thermal treatment procedure
• Immediately implementation following materials synthesis without significant changes to processing conditions or significant capital expenditures
• Significantly reduction of the severity of electrolyte decomposition reactions
• Superlative high-power performance
• Increased volumetric power density

PUBLICATIONS
Lim JM, Luu N, Park KY, Tan M, Kim S, Downing J, He K, Dravid VP and Hersam M (2020) Enhancing nanostructured nickel-rich lithium-ion battery cathodes via surface stabilization. Journal of Vacuum Science & Technology A. 38: 063210.

IP STATUS
A provisional application has been filed.