Preparation of COF@NF as a Host Material and Its Inhibition of Lithium Dendrites
At present,the development of lithium-ion batteries is limited by energy density,which lead to the difficulty of developing more than 300 Wh∙kg-1 lithium-ion batteries.Thus,researchers have to find new anode materials to replace the conventional graphite anode.Lithium metal has the advantages of a theoretical specific capacity of up to 3 860 mAh∙g-1,the lowest chemical reduction potential(-3.04 V vs standard hydrogen electrode),and low density(0.53 g∙cm-3),which makes it an ideal anode material for the next generation of lithium-sulfur and lithium-air batteries.However,due to the"host-free"nature of lithium metal,batteries often face challenges such as volume expansion and difficult to control lithium dendrite growth during the charge-discharge cycle,which greatly hinders the practical use of lithium metal anode.Studies have shown that constructing a lithium-philic interface to induce uniform deposition of lithium metal is an effective method to solve the above problems.At the same time,the three-dimensional structure can significantly reduce the absolute current density of the battery,which is helpful for the stable cycle of the battery at high current.In this paper,the surface of nickel foam was modified by using triazine-based organic framework materials(t-COFs)as a lithium-philic interface,and the modified nickel foam was used as the host of lithium metal anode to inhibit the growth of dendrites.The results show that the t-COF@NF-Li half cell can cycle stably for 400 cycles while maintaining a high average coulomb efficiency and low voltage polarization under a current density of 3.0 mA∙cm-2 and a deposition capacity of 1.0 mAh∙cm-2.Additionally,the t-COF@NF-Li//Li symmetric cell can cycle stably for 600 h and maintain a small overpotential of 20 mV under a current density of 1.0 mA∙cm-2 and a deposition capacity of 1.0 mAh∙cm-2.The excellent electrochemical properties indicate that it is feasible to construct a lithium-philic interface on the foam nickel skeleton for inhibiting the formation of lithium dendrites,and this method holds great significance for constructing high-performance lithium metal batteries.
lithium metal anodelithium dendriteshost materialsCOFs layercyclic stabilitythree-dimensional structurelithiophilic interfacelong cycle
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