A high Li-ion diffusion kinetics in multidimensional and compact-structured electrodes via vacuum filtration casting

Manufacturing process, diffusion co-efficient and areal capacity are the three main criteria for regulating thick electrodes for lithium-ion batteries (LIBs). However, simultaneously regulating these criteria for LIBs is desirable but remains a significant challenge. In this work, niobium pentoxide (Nb2O5) anode and lithium iron phosphate (LiFePO4) cathode materials were chosen as the model materials and demonstrate that these three parameters can be simultaneously modulated by incorporation of micro-carbon fibers (MCF) and carbon nanotubes (CNT) with both Nb2O5 and LFP via vacuum filtration approach. Both as-prepared MNC-20 anode and MLC-20 cathode achieves high reversible areal capacity of ≈5.4 mA h cm−2@0.1 C and outstanding Li-ion diffusion coefficients of ≈10−8 cm2 s−1 in the half-cell configuration. The assembled MNC-20||MLC-20 full cell LIB delivers maximum energy and power densities of 244.04 W h kg−1 and 108.86 W kg−1, respectively. The excellent electrochemical properties of the as-prepared thick electrodes can be attributed to the highly conductive, mechanical compactness and multidimensional mutual effects of the MCF, CNT and active materials that facilitates rapid Li-ion diffusion kinetics. Furthermore, electrochemical impedance spectroscopy (EIS), symmetric cells analysis, and in-situ Raman techniques clearly validates the enhanced Li-ion diffusion kinetics in the present architecture.