Electrochemical fabrication of porous Sn/SnSb negative electrodes from mixed SnO2–Sb2O3

• Porous metal electrodes prepared by direct electro-reduction of oxide precursors.
• High capacity porous Sn/SnSb negative electrodes for lithium ion batteries.
• Pore-forming of Sn/SnSb anode by NH4HCO3 for enhanced electrochemical performances.

Porous Sn/SnSb negative electrodes for lithium ion batteries were directly prepared by electro-reduction of the SnO2–Sb2O3 (molar ratio = 4:1) composite electrodes in 1 mol/L H2SO4. After the reduction, the original dense SnO2–Sb2O3 composite electrode changed into a porous structure with the oxides almost completely reduced to nanoparticles of Sn and SnSb alloy. As the precursor electrode showed very poor electrochemical performances in lithium ion batteries, the resultant metallic porous Sn/SnSb electrode exhibited high charge capacity (800 mAh/g) and good cycling stability (70% of capacity retention at the 40th cycle) between 0.02 and 1.5 V (vs. Li/Li+) at a current density of 100 mA/g. More porous Sn/SnSb electrode was derived from the SnO2–Sb2O3 composite precursor using pore-forming by NH4HCO3 (15 vol.%), showing enhanced electrochemical performances with an initial capacity of 900 mAh/g at 100 mA/g, and 520 mAh/g at 1 A/g at the 40th charging–discharging cycle.