A facile method for determining a suitable voltage window for an amorphous Li12Si7 anode

• A facile method for optimizing the working voltage of Si electrodes was proposed.
• The change in charge transfer resistance indicates the electrode pulverization.
• A suitable voltage window of 0.11 − 0.7 V was determined for a Li12Si7 electrode.
• The cyclability of a Li12Si7 electrode was improved by cycling at 0.11 − 0.7 V.

We report the first attempt to retard the pulverization of an amorphous Li12Si7 anode by controlling the working voltage window. The suitable working voltage window for the amorphous Li12Si7 anode was determined to be 0.11 − 0.7 V by analyzing the change in the charge transfer resistance using electrochemical impedance spectroscopy. After 100 cycles, the capacity retention of the Li12Si7 electrode cycled at 0.11 − 0.7 V increased to 57.6% from the 18.2% capacity retention obtained for the electrode cycled at 0.02 − 2.0 V, representing more than a 2-fold enhancement. SEM observations displayed the limited pulverization and fracture for the electrode cycled at 0.11-0.7 V, which is the most important reason for the improved cycling stability. The methodology presented in this work can be extended to other electrode materials for Li-ion batteries that undergo large volume changes during lithiation/delithiation.