Preparation and Energy Storage of Ellipsoidal Porous Micron Silicon Anode Material Coated with Nitrogen-Doped Carbon Layer
Silicon(Si),with its high theoretical specific capacity(4 200 mAh∙g-1)and excellent lithium intercalation capacity,is considered a promising anode material for next-generation of lithium-ion batteries,potentially replacing graphite.In recent years,a variety of nano-and micro-scale silicon structures,such as nano-silicon wires,hollow spheres,have been developed.Compared with expensive nano-silicon materials,micro-silicon materials are gaining attention due to their high capacity and low cost.However,micro-silicon anode materials face challenges such as volume expansion and pulverization during lithium intercalation and deintercalation,leading to low initial coulombic efficiency and rapid capacity decay over long cycles.This study applies micron-sized Al-Si alloy balls as precursors to synthesize an ellipsoidal,porous micro-silicon coated with nitrogen-doped carbon layer(CPSi@CN)composite material through dual acid etching and in-situ polymerization.Results indicate that the porous structure of CPSi@CN composites effectively mitigates silicon's volume expansion during cycling and enhances ion transport.The surface nano-carbon layer modulates volume expansion and minimizes side reactions,improving cycle stability.Additionally,nitrogen doping enhances ion transport capacity and conductivity of the carbon layer,increasing active sites.As an anode material for lithium-ion batteries,CPSi@CN maintains a specific capacity of 705.16 mAh∙g-1 after 100 cycles at a loading of 2.4 mg∙cm-2 and a current density of 1.0 A∙g-1,acheving an initial coulombic efficiency of 80%.In rate capability tests,it delivers a specific capacity of 429.97 mAh∙g-1 at a current density of 5.0 A∙g-1 and retains 92%capacity when returned to 0.2 A∙g-1.The nitrogen-doped carbon-coated ellipsoidal porous micron silicon anode material coated shows high initial coulombic efficiency,excellent rate capability,and outstanding cycling stability,showing significant promise as a high-performance anode material for lithium-ion batteries in electric vehicles and energy storage applications.
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维普
