A novel strategy for the synthesis of highly stable ternary SiOx composites for Li-ion-battery anodes

Abstract

SiO_x is a promising anode material for lithium-ion batteries (LIBs) due to its relatively high capacity. Nevertheless, the poor conductivity and large volume expansion of SiO_x upon Li⁺ insertion/extraction limit its application. Herein, a novel strategy for preparing ternary Ni/SiO_x/nitrogen-doped carbon (NSC) composites has been developed through in situ transformation of a Ni₃Si₂O₅(OH)₄/nitrogen-doped carbon precursor derived from dried bamboo leaves. The 3D interconnected SiO_x/nitrogen-doped carbon (SC) framework provides sufficient void spaces for relieving the volume change during the lithiation process while facilitating electrolyte infiltration and lithium ion diffusion processes. The growth of uniform Ni nanoparticles (NPs) on the surface of the SC matrix restricts the formation of cracks, reduces volume expansion during the lithiation process, and effectively improves the electrical conductivity of SiO_x. The optimized sample delivers a high discharge capacity of 864.6 mA h g⁻¹ after 70 cycles at 200 mA g⁻¹ and a superior rate capability of 289.8 mA h g⁻¹ at 10 A g⁻¹. The electrode delivers a capacity of 427.6 mA h g⁻¹ even at 5 A g⁻¹ after 1000 cycles along with outstanding capacity retention (∼100%). Our method provides insight into the utilization of biomass towards high performance energy storage through simple and low-cost procedures.