Surface Modification Of Three Dimensional Current Collector For Stable Lithium Metal Anode

With the vigorous development of industrialization,traditional lithium-ion batteries with low energy density have been unable to meet people’s increasing material needs.Li metal has the high energy density,the high specific capacity(3860 m A h g^-1)and lowest operation potential（-3.04 V vs standard hydrogen electrode）,so the Li metal battery（LMB）becomes the ultimate choice for the next-generation energy storage devices.However,the practical application of LMB is limited by the growth of Li dendrites and the volume change of Li metal anodes.To relieve the issues of Li metal anodes,the following work has been carried out in this paper:（1）Study on the Performance of Nickel Nanoparticles Modified Substrates for Lithium Metal AnodesTargeting on the Li dendrites growth and volumetric change during Li stripping/plating of Li anodes,this study reported the CFs/Ni NPs could be obtained by surface nanocrystallization strategy to improve the cycling stability of Li metal anodes.The substrates with Ni nanoparticles significantly reduce the nucleation overpotential of Li and promote uniform Li deposition free of dendrites.The obtained anode exhibits a stable voltage profile with a low voltage hysteresis of less than 20 m V for over 2000 h at 0.5 m A cm^-2 in a symmetrical cell owing to Ni nanoseeds in the 3D scaffold.Equipped with the fabricated Li metal anode,a rechargeable Li metal battery with Li Fe PO₄ cathode that features a high areal capacity of over 3 m A h cm^-2 and high capacity retention of 91.7%for330 cycles at 0.5 C is achieved.（2）Mechanism of Metal Nanoparticles on the Wettability of Molten LithiumTargeting on the problems of poor wettability of the substrate to molten Li and unstable interface contact,this study based on the previous chapter illustrate the wettability of molten Li toward substrates can be tuned by metal（Ni,Cu,Fe）nanoparticles via surface nanocrystallization strategy,and explore the effect and mechanism of metal nanoparticles on the wettability of molten Li.Compared with bare substrates,Ni foil,and Ni foam,substrates with Ni nanoparticles significantly show the stronger lithiophilic with molten Li and improve the cycle performance of Li metal anodes.The nanocrystallization structural features result in a surface energy reduction and generation of Laplace pressure,with both factors acting together to achieve a rapid adsorption of Li.