Direct electrochemical reduction of solid Bi2O3 to Bi as a high-performance anode for sodium-ion batteries using deep eutectic solvent

The direct reduction of solid Bi 2 O 3 to Bi used for a high-performance anode is studied for the first time. Cyclic voltammetry results indicate that the conversion of solid Bi 2 O 3 is a one-step process. Electrolysis measurements using a solid Bi 2 O 3 cathode were carried out at various experimental conditions. X-ray diffraction (XRD) measurements of the electrolytic samples reveal that the solid Bi 2 O 3 can be completed reduced to Bi. The electrolytic Bi obtained at 2.6 V for 6 h achieves a long and steady cycle, a higher specific capacity than 403.2 mAh g −1 , and a higher capacity retention than 95.5 % cycling for even 4000 cycles, as well as an excellent rate capability. The electrochemical deoxidation approach can provide a green and straightforward pathway for producing high-performance sodium-ion batteries anodes.