Distinctive conductivity improvement by embedding Cu nanoparticles in the carbon shell of submicron Si@C anode materials for LIBs

Silicon (Si) possesses a high specific capacity (4200 mA h g(-1)) as the anode of lithium-ion battery (LIBs). However, the huge volume change during lithium intercalation/deintercalation is a big challenge. In this work, submicron Si waste in the kerf waste from the photovoltaic industry was used as the raw material, and a Si@C-Cu core shell structure was fabricated by the hydrothermal process. The copper (Cu) nanoparticles were successfully embedded in the carbon shell, which not only brought about a distinctive improvement in the conductivity of the Si@C anode but also strengthened the carbon shell due to the catalytic graphitization by Cu nanoparticles so as to better withstand the expansion stress from Li+ intercalation in Si. As a result, the initial specific discharge capacity of the Si@C-Cu anode was 3441 mA h g(-1) with a coulombic efficiency of 63.8%, and it retained 2024 mA h g(-1) after 250 cycles at a current density of 0.2C (1C = 4200 mA g(-1)). Moreover, it maintained 1572 mA h g(-1) at a current density of 1.0C, which recovered to about 3000 mA h g(-1) when the current rate returned to 0.1C. This highlights the promising potential of the novel material formed by embedding Cu nanoparticles in the Si@C sphere as an anode in lithium-ion batteries.

Automated summary

In this study, a Si@C-Cu core shell structure was fabricated by embedding Cu nanoparticles in the carbon shell of submicron Si waste. The resulting Si@C-Cu anode showed improved conductivity and enhanced strength, enabling it to withstand the expansion stress from lithium intercalation in Si. It exhibited high specific discharge capacity and coulombic efficiency, indicating its promising potential as an anode material for lithium-ion batteries.