Study On The Application Of Nitrate Modified Threedimensional Current Collectors For Stable Lithium Metal Anode

Lithium metal anode（LMA）is perceived as ideal anode material for next-generation high-energy batteries due to its ultra-high theoretical specific capacity and the lowest redox potential.The application of LMAs is limited by several problems such as:dendrites growth,SEI（Solid Electrolyte Interface）reconstruction and huge volume expansion during cycling.The three-dimensional（3D）current collector is a potential host material for LMAs.Its inherent 3D structure and high specific surface area can effectively solve the issues of volume expansion and dendrite growth of LMAs.However,the SEI on the surface is fragile and the parasitic reactions induced by the electrolyte and metallic Li are still serious.In this work,inorganic nitrate modified 3D current collectors were used to obtain composite LMAs,which exhibited excellent cycling stability in a carbonate-based electrolyte.The specific research contents are as follows:（1）A copper foam preloaded with lithium nitrate（Li NO₃）was prepared by a facile aqueous solution method.And a composite LMA based on the modified copper foam was obtained.The modified copper foam（T-CF）can relieve the huge volume expansion of the LMA during cycling and prolong the period of dendrites growth.The decomposition of Li NO₃ can lead to the formation of an SEI rich in Li₃N and Li_xNO_y.Thus,improved cycling performances of the LMAs based on the T-CF（T-CF@Li）were achieved in carbonate electrolyte.The half-cell based on T-CF exhibited an average coulombic efficiency（CE）as high as 99%for 300 cycles under the conditions of 1 m A cm^-2 with a cutoff capacity of 3 m Ah cm^-2.The T-CF@Li anodes showed superior cycling performance in full cells when coupling with the lithium iron phosphate（LFP）or the ternary（NCM）cathodes.The T-CF@Li-LFP full cell displayed a capacity retention of 95%after 300 cycles.And the T-CF@Li-NCM full cell exhibited a capacity retention of 70%after 250 cycles.（2）Using a carbon paper（CP）as the 3D host,a composite LMA（Ag N-CP@Li）containing Li NO₃ and Ag nanoparticles（NPs）was obtained based on the reaction molten Li and silver nitrate（Ag NO₃）,the Ag NO₃ was introduced into carbon paper by the method described in（1）.The decomposition of Li NO₃ would induce a N-rich SEI film.The Ag NPs can reduce the nucleation barrier of lithium ions and induce the uniform deposition of metallic Li.Therefore,the Ag N-CP@Li anode showed improved cycling stability in the carbonate electrolyte.The half-cell based on Ag N-CP showed an average CE of 99%under the test conditions at 1 m A cm^-2 with a cutoff capacity of1 m Ah cm^-2 over 200 stable cycles.The assembled Ag N-CP@Li-LFP full cells displayed a capacity retention of 95%after 300 cycles,and the Ag N-CP@Li-NCM battery showed a capacity retention of 90%after 200 cycles.In this work,the prepared composite LMAs based on the nitrate-modified 3D current collectors exhibited excellent cycling performance in commercial carbonate electrolytes.This work shed a light on development of the practical application of LMA.