Revealing the fundamentals of lithium-metal microbatteries

Microbatteries play a crucial role in many emerging technologies. Lithium-metal microbatteries are a promising device for these applications, but they suffer from poor production sustainability, as well as safety and performance issues stemming from improper insulation and encapsulation of the battery cells. Collins et al. sought to better understand this device and reported their findings from three separate experiments.

First, the authors packaged Li-metal microbatteries using photoresist, a low-cost material often used in semiconductor microfabrication, and found that it works as a temporary hermetic encapsulation material for the cells.

For the second experiment, they applied high stress currents to the encapsulated microbatteries during the interlayer formation process. The currents sped up the interlayer formation process, demonstrating that this technique could increase the efficiency of Li-metal microbattery cell manufacturing. This experiment also allowed them to determine the viability of a deposited lithium anode versus one grown in situ.

Finally, the authors examined the performance of two types of bilayer anodes in well-encapsulated cells during Li-metal plating. The Li-blocking bilayer, made of a nickel-copper anode, exhibited high discharge capacity and minimal cell corrosion at high charge rates. The Li-nucleating bilayer, made of a gold-copper anode, displayed the opposite effect: high discharge capacity and minimal corrosion at lower charge rates. According to the authors, bilayer materials like the nickel-copper anode could meet consumer demands for high charge rate, high capacity rechargeable microbattery cells.

“Next generation energy storage is on the horizon,” said author John Collins. “I am so happy and grateful to present this fundamental piece of the solid-state battery puzzle.”

Source: “Fundamentals, impedance, and performance of solid-state Li-metal microbatteries,” by John Collins, Joel P. de Souza, Yun Seog Lee, Adele Pacquette, John M. Papalia, Douglas M. Bishop, Teodor Todorov, Mahadevaiyer Krishnan, Eric Joseph, John Rozen, and Devendra Sadana, Journal of Vacuum Science & Technology: A (2020). The article can be accessed at https://doi.org/10.1116/6.0000097 .