Sodium (Na) metal is the most promising alternative for lithium metal as an anode material for the next-generation energy storage systems. However, its practical implementation has been hindered by the huge volume change and severe dendrite growth of Na metal during repeated electrochemical stripping/plating. Herein, we present the use of a chemically engineered porous copper (Cu) matrix as a stable host for metallic Na anode. By treating the commercially available Cu foam through a facile and cost-effective method, a composite matrix consisting of cylindrical core-shell skeleton has been achieved, facilitating uniform impregnation and confinement of Na within the matrix pores promoted by the chemical interaction between Na and the matrix. More important, the unique surface characteristic of the matrix can divert the Na deposition from the skeleton towards the Na reservoirs within the pores upon cycling, significantly suppressing the volume change and mossy/dendritic Na growth. A stable Na cycling behavior with flat voltage profile and small voltage hysteresis has been demonstrated in carbonate electrolyte without any additives at a high capacity up to 3 mAh cm-2 with a current density up to 2 mA cm-2. A stable rate performance of Na anode up to 3 mA cm-2 is also demonstrated. Moreover, electrochemical measurements of a full cell made of Na3V2(PO4)3 as cathode and the as-prepared surface-treated Na composite matrix as anode clearly reveal the superior performance at high current rate (5C) over that using bare Na metal as anode.

Chemically-engineered porous copper matrix with cylindrical core-shell skeleton as a stable host for metallic sodium anode

256th National Meeting (2018)

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