Layered Ag-graphene films synthesized by Gamma ray irradiation for stable lithium metal anodes in carbonate-based electrolytes

Abstract

Lithium metal batteries are considered as high energy density battery systems with very promising prospects and have been widely studied. However, The uncontrollable plating/stripping behavior, infinite volume change and dendrites formation of lithium metal anode restrict the application. The uncontrolled nucleation of lithium caused by the nonuniform multi-physical field distributions, can lead to the undesirable lithium deposition. Herein, a graphene composite uniformly loaded with Ag nano-particles (Ag NPs) is prepared through a facile Gamma ray irradiation method and assembled into self-supported film with layered structure (Ag-rGO film). When such film is used as a lithium metal anode host, the uncontrolled deposition is converted into a highly nucleation-induced process. On one hand, the Ag NPs distributed between the interlayers of graphene can preferentially induce lithium nucleation and enable uniform deposition morphology of lithium between interlayers. On the other hand, the stable layered graphene structure can accommodate volume change, stabilize the interface between anode and electrolyte and inhibit dendrites formation. Therefore, the layered Ag-rGO film as anode host can reach a high Coulombic efficiency over 93.3% for 200 cycle (786 h) at a current density of 1 mA cm−2 for 2 mAh cm−2 in carbonate-based electrolyte. This work proposes a facile Gamma ray irradiation method to prepare metal/3D-skeleton structure as lithium anode host and demonstrates the potential to regulate the lithium metal deposition behaviors via manipulating the distribution of lithiophilic metal (e.g. Ag) in 3D frameworks. This may offer a practicable thinking for the subsequent design of the lithium metal anode.