Synthesis, Electrochemistry, and Thermal Stability of High‐Energy Ball‐Milled Silicon‐based Alloy Anodes in Lithium‐Ion Batteries

Doping silicon-based alloy anodes: NiO was introduced into the Si−CuO system via a HEBM method. The study revealed that excessive CuO could negatively affect the cycle performance, but the Si−CuO−NiO samples showed improved capacity retention. In addition, the thermal stability test suggested that 600 °C was acceptable temperature for coating a carbon layer due to the ideal microstructure and element distribution.

Abstract

The fast capacity degradation of silicon-based anodes significantly limits the application in lithium-ion battery (LIB) industries. Recently, Si−CuO composites have been reported as promising anodes in terms of being cost-effective and technically feasible, but improved cycle stability is still desired. This work introduces a proper amount of NiO into the Si−CuO composites via a facile high-energy ball-milling method. The study reveals that compared to the binary Si-CuO composites, Si−CuO−NiO samples have less pronounced volume change during the cycles due to the formation of rich-Si NiSi₂. More specifically, Si_87.5(CuO)_3.4(NiO)_9.1 shows the highest 100-cycle capacity retention of ∼86.9 % at 0.2 C with an average coulombic efficiency of ∼99.4 %. Moreover, the thermal stability investigation demonstrates that the temperature of 600 °C is suitable to coat a carbon layer on Si_87.5(CuO)_3.4(NiO)_9.1, where the microstructure and the uniform element distribution produced in the milling process as well as the suppression to the cr-Li_3.75Si formation can be maintained to the maximum extent, thus with further enhanced electrochemical performance.

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