摘要
Abstract
To address the growing demand for fast-charging lithium-ion batteries in electric vehicles,large-scale energy storage systems,and portable electronic devices,and to overcome the sluggish ion transport kinetics,severe polarization,and limited cycle life exhibited by conventional electrodes under high-current operating conditions,this study investigates the design of a multiscale three-dimensional conductive network architecture and its optimization for enhanced ion transport.First,based on characteristic time constant theory,the kinetic relationship between electron conduction and ion diffusion during fast charging is quantitatively analyzed,demonstrating that ion transport becomes the dominant rate-limiting factor at charging rates above 10 C.Accordingly,a design strategy based on dual continuity and kinetic matching of electron and ion transport pathways is proposed.The mechanisms by which the three-dimensional conductive network reduces transport resistance and mitigates polarization by establishing efficient electron-conduction pathways and optimized ion-diffusion channels are systematically elucidated.An evaluation framework centered on the dimensionless structural efficiency factor(β=ε/τ)is established,and a hierarchical collaborative design strategy spanning the micro-,meso-,and macro-scales is developed to identify the optimal structural parameters at each scale.A multiscale,multiphysics numerical model is established using COMSOL Multiphysics 6.0 with clearly defined modeling assumptions and applicability ranges(porosity 30%—55%;graphene content 2%—5%;charging rate:≤12 C).Multi-objective optimization using response surface methodology enables precise matching between structural parameters and transport performance.The electrodes are fabricated using an integrated process combining three-dimensional printing,in situ sintering,and dispersion techniques,achieving a production rate of 50 electrodes per hour and a material utilization efficiency exceeding 95%,thereby demonstrating strong potential for scalable manufacturing.Electrochemical characterization shows that the optimized electrode delivers a specific capacity of 138 mAh/g at a high charging rate of 10 C,with a coulombic efficiency of 94.5%and a capacity retention of 91.3%after 1000 charge-discharge cycles.The optimized architecture increases the lithium-ion diffusion coefficient to 1.2×10-11 cm2/s and reduces the charge-transfer resistance to 75 Ω·cm2.Additionally,the electrode maintains excellent electrochemical performance over a wide operating temperature range,from-20℃to 55℃.Finally,the broader applicability of the proposed multiscale design strategy is discussed for silicon anodes,sulfur cathodes,and composite solid-state electrolyte electrodes.Remaining challenges,including the long-term stability of ZrO2 coating layers and interfacial fatigue mechanisms,are also identified.These findings provide valuable theoretical guidance and practical support for the industrial development of high-rate,fast-charging lithium-ion batteries.关键词
锂离子电池/快充技术/三维导电网络/离子传输/特征时间常数Key words
lithium-ion battery/fast charging technology/three-dimensional conductive network/ion transport/characteristic time constant分类
信息技术与安全科学
