Carbon layers with microporous structures fine-modulated by naphthalene(NAP) were prepared to coat on LiFePO_4, aiming to enhance the Li+diffusion coefficient for Li-ion batteries. Characterized by BET, XRD, TEM, EIS,...Carbon layers with microporous structures fine-modulated by naphthalene(NAP) were prepared to coat on LiFePO_4, aiming to enhance the Li+diffusion coefficient for Li-ion batteries. Characterized by BET, XRD, TEM, EIS, etc., it is indicated that in the presence of NAP, the carbon-coated LiFePO_4/C-NAP composites have the enlarged micropore size of 1.66 nm and the enhanced Li^+ diffusion coefficient of2.83 × 10^(-12)cm^2s^(-1), which is about five times higher than that of LiFePO4/C prepared in the absence of NAP. At a high rate of 20 C, the discharge capacity of the LiFePO_4/C-NAP is up to 120.1 mA h g^(-1) and maintains a good retention rate of 93.2% after 400 cycles. It is suggested that the NAP-modulated carbon coating is a promising route to accelerate the Li-ion diffusion rate and enhance the electrochemical performance for lithium ion batteries.展开更多
A bidisperse model for transient diffusion and adsorption processes in porous materials is presented in this paper.The mathematical model is solved by numerical methods based on finite elements combined with the linea...A bidisperse model for transient diffusion and adsorption processes in porous materials is presented in this paper.The mathematical model is solved by numerical methods based on finite elements combined with the linear driving force approximation.A criterion based on the model to identify the diffusion controlling mechanism(macropore diffusion,micropore diffusion,or both)is proposed.The effects of different adsorption isotherms(linear,Freundlich,or Langmuir)on the concentration profiles and on curves of fractional uptake versus time are investigated.In addition,the influences of model parameters concerning the pore networks on the fractional uptake are studied as well.展开更多
基金financially supported by the National Natural Science Foundation of China(Nos.21476158,21621004)Program for Changjiang Scholars and Innovative Research Team in University(No.IRT_15R46)
文摘Carbon layers with microporous structures fine-modulated by naphthalene(NAP) were prepared to coat on LiFePO_4, aiming to enhance the Li+diffusion coefficient for Li-ion batteries. Characterized by BET, XRD, TEM, EIS, etc., it is indicated that in the presence of NAP, the carbon-coated LiFePO_4/C-NAP composites have the enlarged micropore size of 1.66 nm and the enhanced Li^+ diffusion coefficient of2.83 × 10^(-12)cm^2s^(-1), which is about five times higher than that of LiFePO4/C prepared in the absence of NAP. At a high rate of 20 C, the discharge capacity of the LiFePO_4/C-NAP is up to 120.1 mA h g^(-1) and maintains a good retention rate of 93.2% after 400 cycles. It is suggested that the NAP-modulated carbon coating is a promising route to accelerate the Li-ion diffusion rate and enhance the electrochemical performance for lithium ion batteries.
基金financial support by the National Natural Science Foundation of China(Grant No.91534120)China National Petroleum Company under the contract number DQZX-KY-17-019
文摘A bidisperse model for transient diffusion and adsorption processes in porous materials is presented in this paper.The mathematical model is solved by numerical methods based on finite elements combined with the linear driving force approximation.A criterion based on the model to identify the diffusion controlling mechanism(macropore diffusion,micropore diffusion,or both)is proposed.The effects of different adsorption isotherms(linear,Freundlich,or Langmuir)on the concentration profiles and on curves of fractional uptake versus time are investigated.In addition,the influences of model parameters concerning the pore networks on the fractional uptake are studied as well.
