Innovative Nanoscale Ceramic Separators to Boost Cycle Life and Cycle Efficiency of Lithium Metal Batteries

Abstract

In the pursuit of advancing energy storage, the extraordinary theoretical specific capacity of lithium metal at 3,860 mAh/g significantly outperforms traditional graphite anodes, which offer a capacity of around 372 mAh/g. This disparity underscores the potential of lithium metal batteries to facilitate a leap in energy density, heralding a new age of high-performance batteries. Yet, the evolution of lithium metal batteries is hindered by the formation of dendritic structures during repetitive cycling, posing serious risks, including the likelihood of short circuits that underscore severe safety concerns. To mitigate these risks and enhance the longevity of lithium metal anodes, extensive research has been dedicated to various strategies, including surface modifications of lithium metal and the application of innovative coatings on separators. These strategies, however, often compromise energy density and ionic conductivity due to the addition of ceramic materials and binders. Our study introduces a groundbreaking approach that utilizes nanoscale ceramic-coated separators, created via electron beam deposition. This method achieves a consistent nanoscale spread of metal oxide particles on conventional polyethylene (PE) separators. Crucially, this technique ensures even lithium-ion flow and greatly reduces dendrite growth. The effectiveness of this innovative approach was confirmed in comprehensive LiFePO4-Li cell tests, where cells with these ceramic-coated separators showed notable improvements in both cycle life and Coulombic efficiency, representing a significant advancement over traditional methods.