Charging into the future with new electroactive lithium host for high-energy-density lithium metal batteries
Scientists from Korea have proposed a new electroactive lithium host based on a microgrid-patterned silicon electrode.
Research published online in Energy & Environmental Science in April 2022
Lithium-metal batteries can potentially meet our growing high energy demands, but suffer from electrochemically inert constituents. Now, a study by scientists from Korea proposes a new electroactive lithium host based on a microgrid-patterned silicon electrode as a promising platform for developing high-energy-density lithium-metal batteries.
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Over the last two decades, there has been a surge in demand for wireless electronics, electric vehicles, and large-scale energy storage systems. This has entailed the development of high-energy-density lithium (Li)-metal batteries as a superior alternative to traditional Li-ion batteries.
Li metal has garnered considerable attention as an ideal anode material owing to its high theoretical capacity and low redox potential. However, several drawbacks, such as unstable Li plating/stripping that leads to uncontrollable growth of Li dendrites, have limited the practical application of Li-metal batteries. Additionally, the dendrite growth results in continuous consumption of electrolytes, unstable solid-electrolyte interphase (SEI), and generation of dead (inactive) Li, eventually deteriorating the cycle life of the batteries.
One way to overcome these challenges, as several studies suggest, is to switch to what are called “three-dimensional structured Li hosts.” The specialty of this architecture lies in their high surface area, enabled by pore spaces that allow confined Li deposition and reduce local current density without significant changes in volume. Unfortunately, most Li hosts reported so far have not yet fulfilled the requirements of lithiophilicity (strong affinity for Li), electrical conductivity, and porosity simultaneously. Further, these hosts often have electrochemically inert constituents, resulting in undesired loss of gravimetric/volumetric energy densities.
Against this backdrop, a research team from Korea, led by Professor Sang-Young Lee from Yonsei University, proposed a microgrid-patterned silicon (MPS) electrode as a new electroactive (as opposed to “inert”) Li host for the fabrication of high-energy-density Li-metal batteries. Their research, published recently in Energy & Environmental Science, could revolutionize the energy industry by making high-energy-density batteries feasible and practical.
The team designed the MPS host using a technique known as “microscale direct ink writing.” They then tuned its lithiophilicity, electrical conductivity, and porous structure to guide the flow of Li ions and electrons into the MPS pores and ensure electrochemical reversibility at the same time.
The MPS host thus created achieved a stepwise sequential Si lithiation/delithiation from the Si embedded inside the microgrids (Si-anode mode) and Li metal plating/stripping (Li-metal mode) inside the pores between the microgrids, pointing to a unique electrochemical feature of the MPS host. Moreover, a Li metal full cell designed using this MPS host showed high gravimetric/volumetric energy densities (644 Wh kgcell-1/1,538 Wh Lcell-1) and stable cycling capacity.
With these encouraging results, the electroactive MPS host strategy could finally open doors to practical high-energy-density Li-metal batteries. Moreover, the technology is versatile. “The MPS strategy could be extended to other emerging metal anodes as well. We expect that our research will help make Li-metal batteries a promising long-term solution that will help us realize a fossil-fuel-free society,” concludes Prof. Lee.
We sure hope we are closer to realizing his vision!
Professor Jong-Hyun Ahn
Professor Seong Chan Jun
Professor Donghyun Kim