Efficient Construction And Performance Of Highly Stable Li Metal Anodes Based On 3D Lithiophilic Conductive Framework

In recent years,the graphite anode for lithium-ion batteries（LIBs）has reached theoretical specific capacity of 372 m Ah g^-1.However,the limited practical energy density of LIBs hinders their widespread deployment in the energy storage systems that exhibit the higher power metrics required to facilitate strategic applications,there is imperative to explore alternative higher-energy batteries.Among alternative anode materials,lithium metal is considered as the best choice for anode materials due to its high theoretical specific capacity(3860 m Ah g^-1),low redox potential（-3.040 V for standard hydrogen electrodes）and low density(0.53 g cm^-3 at room temperature).However,there are a number of safety issues that cannot be ignored such as relatively infinite volume expansion and uncontrolled dendrite growth.The current lithium metal composite anode based on a 3D collector structure effectively reduces the current density to suppress lithium dendrite growth and control the volume change during lithium stripping/deposition.This paper focuses on the surface modification of three-dimensional（3D）collector by the means of constructing a lithiophilic layer.The lithium metal can nucleate uniformly on the collector,which improves the safety and reliability.The mainly research are as follows:（1）ZnO nanosheet array modified nickel foam skeleton was prepared by hydrothermal method and pre-plated with lithium by the process method of lithium thermal infusion by melt method to obtain a novel dendrite free Li@ZnO-NF composite negative electrode.The uniformly distributed ZnO nanosheet arrays can improve the lithiophilic of nickel foam and regulate the uniform nucleation of lithium,resulting in a more uniform lithium stripping/plating behaviour.At the same time,the ZnO-NF skeleton has a high porosity,which also leads to a significant increase in the specific surface area of the 3D skeleton material.The increased specific surface area means that the local current density of the collector fluid is reduced,which can inhibit dendrite growth.In addition,the 3D porous structure of nickel foam accommodates the large volume changes during the stripping/plating process.Using Li@ZnO-NF composite anode to assemble a symmetric cell,the cell achieves a very smooth stripping/plating curve with no significant fluctuations at a current density of 1 m A cm^-2,with a relatively low overpotential（16 m V）at an ultra-long cycle life（1000 h）.In addition,the multiplicative capacity and long cycle stability of the full cell（80.3%capacity retention after 450 cycles at 1 C）were achieved in a full cell paired with a Li Fe PO₄ cathode.（2）Carbon cloth skeleton structure modified by CuO nanorod arrays was prepared by hydrothermal method,and a new type of dendrite free Li@CuO-CC composite anode was obtained by the process method of lithium thermal infusion by melt method for lithium preplating.The three-dimensional porous skeleton structure of carbon cloth,with its strong and tough skeleton and large specific surface area,can adapt to the volume change effect generated by the battery during cyclic charging and discharging and can disperse the current to reduce the current density.In addition,the lithiophilic capability of CuO is expected to facilitate the uniform diffusion and deposition of lithium on carbon cloth during charging.Li@CuO-CC composite anode assembled symmetric cells have a very stable stripping/plating curve at a current density of 1 m A cm^-2,with a very low overpotential（12 m V）at long cycle life（1000 h）while no significant fluctuations occurred.In addition,the Li@CuO-CC composite negative in a full cell paired with a Li Fe PO₄ cathode assembly showed excellent cell multiplicity performance and long cycle stability（78.9%capacity retention after 600 cycles at 1 C）.