Defect-induced plating of lithium metal within porous graphene networks

Lithium metal is known to possess a very high theoretical capacity of 3,842 mAh g −1 in lithium batteries. However, the use of metallic lithium leads to extensive dendritic growth that poses serious safety hazards. Hence, lithium metal has long been replaced by layered lithium metal oxide and phospho-olivine cathodes that offer safer performance over extended cycling, although significantly compromising on the achievable capacities. Here we report the defect-induced plating of metallic lithium within the interior of a porous graphene network. The network acts as a caged entrapment for lithium metal that prevents dendritic growth, facilitating extended cycling of the electrode. The plating of lithium metal within the interior of the porous graphene structure results in very high specific capacities in excess of 850 mAh g −1 . Extended testing for over 1,000 charge/discharge cycles indicates excellent reversibility and coulombic efficiencies above 99%. The use of metallic lithium electrodes in batteries would lead to dendritic growth problems. Here, Mukherjee et al. use porous graphene electrodes to entrap lithium metal at defect sites, achieving much improved specific capacities over extended cycling.