Li metal has been considered an outstanding candidate for anode materials in Li-ion batteries (LIBs) due to its high specific capacity and low electrochemical potential, but addressing the problem of Li dendrite formation has remained a challenge. We managed to develop safer Li metal batteries in two different ways: Introducing a host material to suppress dendrite formation and modifying the separator to detect and block up dendrite growth. We used a porous carbon material made from asphalt (Asp), specifically untreated gilsonite, as an inexpensive host material for Li plating. The ultrahigh surface area of &gt;3000 m2/g (by BET, N2) of the porous carbon ensures that Li was deposited on the surface of the Asp particles, as determined by scanning electron microscopy (SEM), to form Asp-Li. Stable cycling was achieved for more than 500 cycles at 5 A/gLi, and the areal capacity reached up to 9.4 mAh/cm2 at 20 mA/cm2. Full batteries were also built combining the Asp-GNR-Li anodes with a sulfurized carbon cathode that possessed both high power density (1322 W/kg) and high energy density (333 Wh/kg). Furthermore, we developed a red P-coated separator that is able to detect Li dendrite growth by showing a sharp voltage increase in the charging profile of the full cell. Red P is also capable reaction with Li metal which prevents dendrites from penetrating the separator and shorting and batteries. We believe by both suppression and detection of dendritic Li metal structures, we could help revive the use of Li metal as a high-performance anode material in real batteries.

Safe lithium metal batteries enabled by asphalt and red phosphorus

256th National Meeting (2018)

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