Electrolyte and current collector designs for stable lithium metal anodes

With the increasing demand for high energy-density batteries for portable electronics and large-scale energy storage systems, the lithium metal anode (LMA) has received tremendous attention because of its high theoretical capacity and low redox potential. However, the commercial application of LMAs is impeded by the uncontrolled growth of lithium dendrites. Such dendrite growth may result in internal short circuits, detrimental side reactions, and the formation of dead lithium. Therefore, the growth of lithium metal must be controlled. This article summarizes our recent efforts in inhibiting such dendrite growth, decreasing the detrimental side reactions, and elongating the LMA lifespan by optimizing the electrolyte structure and by designing appropriate current collectors. After identifying that the unstable solid electrolyte interface (SEI) film is responsible for the potential dropping in carbonate electrolytes, we developed LiPF₆–LiNO₃ dual-salt electrolyte and lithium bis(fluorosulfonyl)imide (LiFSI)–carbonate electrolyte to stabilize the SEI film of LMAs. In addition, we achieved controlled lithium deposition by designing the structure and material of the current collectors, including selective lithium deposition in porous current collectors, lithiophilic metal guided lithium deposition, and iron carbide induced underpotential lithium deposition in nano-cavities. The limitations of the current strategies and prospects for future research are also presented.