Biphasic Graphene-Oxide Liquid Metal Powder: Synthesis, Characterization, and Application in Energy Storage

Abstract

Nanodroplets of Gallium-Based Liquid Metal (LM) have applications in stretchable electronics, electrochemical sensors, energy storage, hyperthermia, and rapid polymerization. The gallium oxide layer around LMNDs prevents aggregation. However, LM nanodroplets (LMNDs) are neither mechanically nor chemically stable. The ultrathin oxide layer ruptures under slight pressure, hindering their use in stretchable electronics. The shell also dissolves in slightly acidic/alkaline solutions, making them unstable for energy storage and electrochemical sensing. We demonstrate the synthesis of a dry LM powder with an LM core and a reduced graphene oxide shell. Graphene oxide provides excellent mechanical and chemical stability and permits electrical conductivity. Its porous structure does not block ion exchange between the LM droplets and the environment, allowing LMNDs to be used in energy storage and electrochemical sensing. The resulting EGaIn powders benefit from higher surface and long-term stability, addressing LMND limitations. We report using GO@EGaIn nanocomposite as an anode for alkali-ion batteries in a novel Ag-EGaIn cell with impressive energy storage capacity. The combination of liquid deformability of LMNDs, higher surface area in the nano form, and the stability of GO@EGaIn dry powder expands the applications of liquid metals in electronics and energy storage.