Dynamic Concentration of Alloying Element on Anode Surface Enabling Cycle‐Stable Li Metal Batteries

Abstract

The pursuit of high energy density Li‐based rechargeable batteries has intrigued numerous research interest on Li metal anode. However, several significant challenges, including severe parasitic reactions and growth of Li dendrites, lead to fast electrode failure and impede its practical implantation. Herein, it is revealed that the dynamic concentration of alloying element in Li solid solution can significantly improve the cycling stability. It is demonstrated that the alloying element of Li solid solution continuously evolved in the reaction layer on cycling. Alloying element got enriched on anode surface after Li stripping, and re‐dispersed into the deposited Li during Li plating processes. The alloying element‐rich surface can reduce the Li nucleation barrier and promote the uniform Li plating behavior. Ultrathin Li solid solution foils are fabricated, and the dynamic alloying element concentration mechanism is further verified, and the cycling lifespan of pure Li is doubled. Consequently, a 1.4 Ah laminated pouch cell with ultrathin Li solid solution anode (30 µm) exhibits high energy density of 836 Wh L−1 and stable cycling performance under the harsh conditions with low negative/positive capacity (N/P) ratio of 2 and electrolyte/capacity (E/C) ratio of 2.6 g Ah−1.

Hybrid Polymer-Alloy-Fluoride Interphase Enabling Fast Ion Transport Kinetics for Low-Temperature Lithium Metal Batteries

“…The ever-growing demands for highly durable electronic applications in extreme environments (such as high atmosphere, aerospace, polar region, and abysmal sea) necessitate rechargeable batteries with high energy density in all weather conditions, especially at low temperatures (e.g., −20 °C and below). − Commercial lithium-ion batteries (LIBs) using graphite anodes with low theoretical capacity (372 mAh g –1 ) are insufficient in terms of energy density (< 300 Wh kg –1 ) to meet the increasing demand. − Moreover, graphite anode undergoes dramatically reduced capacity and uncontrolled Li plating behavior when operated at subzero temperatures, making it impractical for low-temperature applications. − Metallic Li has been pursued as a preferential anode choice for high-energy-density batteries with a wide operating temperature range because of its high theoretical capacity of 3860 mAh g –1 , low electrochemical potential of −3.04 V (vs standard hydrogen electrode), and operational electroplating/stripping behavior. − In recent years, significant progress has been made in enhancing the energy density and extending the lifespan of Li metal batteries (LMBs) at ambient temperatures. − However, the low-temperature operation of LMBs remains a critical, yet unexplored field.…”

Ionic Layer Epitaxy Growth of Organic/Inorganic Composite Protective Layers for Large-Area Li and Zn Metal Anodes

“…Rechargeable metal batteries using Li metal (3860 mAh g –1 ) and Zn metal (5855 mAh cm –3 ) as anodes are considered the most promising alternatives to conventional Li-ion batteries due to their impressive capacities. − Nevertheless, the cycling stability of these batteries is significantly hindered by the formation of Li and Zn dendrites. − These dendrites grow on a bare metal surface, leading to an increased local current density at their tips, a phenomenon referred to as the “tip effect”, which exacerbates dendrite growth. − In recent years, extensive research has been conducted to understand the deposition/exfoliation processes of Li and Zn ions, , revealing that dendrite formation primarily arises from the nonuniform distribution of ions on the electrode surface. − Therefore, achieving uniform ion nucleation and distribution is essential to suppressing dendrite growth. In this inspiration, various effective strategies dedicated to promoting uniform deposition of Li and Zn ions have been developed. , One particularly successful approach involves employing an anode protection layer.…”