Si/Co-CoSi₂/reduced graphene oxide ternary nanocomposite anodes for Li-Ion batteries with enhanced capacity and cycling stability

다국어 초록 (Multilingual Abstract)

<P><B>Abstract</B></P> <P>Silicon (Si) is a promising anode material for high-performance Li-ion batteries (LIBs), but it undergoes rapid capacity fading through severe volumetric expansion during Li insertion/extraction. Although alloying Si with various metal sources has been pursued to mitigate the structural deterioration, the resulting materials have shown the intrinsic problem of low electrical conductivity. To address this conflicting issue, here we describe a novel ternary nanocomposite of Si/Co-CoSi<SUB>2</SUB>/reduced graphene oxide (rGO) made using a facile process of mechanical mixing of Si nanoparticles, Co<SUB>3</SUB>O<SUB>4</SUB> microparticles, and rGO nanosheets, followed by carbothermal reduction. Specifically, rGO, which has high electrical conductivity and structural integrity, could work as both a conductive matrix and a reducing agent in forming the Co-CoSi<SUB>2</SUB> phase inside the Si domains during thermal treatment. The proposed ternary nanocomposites exhibited a noteworthy specific capacity of 952 mA h g<SUP>−1</SUP> with 79.3% capacity retention after 80 cycles at a current density of 100 mA g<SUP>−1</SUP>. We attribute the improved electrochemical performance to the increased structural stability offered by the Co-CoSi<SUB>2</SUB> phase and the interconnected conductive framework of the rGO nanosheets. Therefore, we expect our design process for Si/Co-CoSi<SUB>2</SUB>/rGO ternary nanocomposites to be applicable to other materials that can eventually be used as high-performance anodes for the next generation LIBs.</P> <P><B>Highlights</B></P> <P> <UL> <LI> A new Si/Co-CoSi<SUB>2</SUB>/rGO ternary nanocomposite is suggested as Li-ion battery anodes. </LI> <LI> An electroconductive yet Li-inactive phase of Co-CoSi<SUB>2</SUB> is incorporated into a Si matrix. </LI> <LI> Encompassing rGO nanosheets provide mechanical stability and conductivity during cycles. </LI> <LI> Ternary nanocomposite exhibits excellent electrochemical performance. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>