具有高理论比容量和最低电极电位的锂金属是极具潜力的下一代锂二次电池负极材料。然而，锂金属负极表面极易产生枝晶和 “死锂”，造成活性物质损失，甚至引发短路、爆炸等安全问题。另外，锂金属沉积/脱出过程中的体积变化会造成表面固态电解质界面层的反复破坏和再形成，并降低电池循环稳定性。针对上述问题，本论文拟从三维集流体设计、二维保护层构建和电解液溶剂结构调控三方面入手，自下而上地调控锂金属的形核、沉积行为，从而达到抑制枝晶生长、提高锂金属负极电化学稳定性的目的，取得了如下创新性成果： （1）针对商用铜箔集流体亲锂性差的问题，提出在其表面原位生长亲锂氧化铜纳米片阵列，实现锂金属的均匀形核及稳定沉积。亲锂纳米片阵列的构建不仅降低了电极的局部电流密度，而且使电极表面电场均匀分布，实现了锂离子的均匀沉积，从而提升了锂负极的库仑效率及循环稳定性。 （2）针对三维集流体内部空间利用率低、严重降低电极比容量等问题，提出在轻质铜纳米线集流体表面构筑梯度亲锂磷化层，实现锂金属在集流体内部的致密沉积。研究揭示该梯度亲锂层可同时保证离子、电子在三维集流体内部的快速传输，将电极整体的质量、体积比容量分别提升至1702.9 mA h/g、1582 mA h/cm3。 （3）设计并制备二维有机-无机复合层状锂金属负极表面保护层，并研究其在酯类电解液中对界面电化学反应的影响，提出发生在界面处的脱溶剂化过程是影响锂金属负极电化学可逆性的重要因素。二维材料的层状结构可作为离子、溶剂分子的纳米筛分通道，在锂离子沉积前实现预先去溶剂化，避免溶剂与活泼锂金属间的副反应，有效将锂金属负极在酯类电解液中的库仑效率提升至94 %。 （4）提出将阻燃稀释剂引入高浓醚类电解液，得到一种阻燃的局部高浓电解液,显著提升了锂金属负极的综合电化学性能及安全性。稀释剂的引入使更多阴离子进入锂离子的溶剂化壳层，有利于形成均匀、稳定的固态电解质界面。该策略有效降低了锂离子的脱溶剂化势垒及电化学反应势垒，使得锂负极在5 mA/cm2电流密度下的库伦效率仍保持97.8 %。 综上所述，本论文通过三维集流体结构设计、界面电化学反应调控、电解液结构优化三方面，自下而上地提升锂金属负极的稳定性及安全性，为推进高能量密度锂金属电池的发展提供借鉴。

Lithium metal anode is a potential candidate for next-generation lithium second-ary batteries due to its high theoretical capacity, lowest electrochemical potential and low density. However, dendrites and “dead lithium” are often generated during plating/stripping, resulting in the loss of active lithium and severe safety problems, such as short circuit and explosion. Moreover, the solid-electrolyte interphase formed on the lithium surface can be easily broken by the inner stress generated from volume change, exposing fresh lithium that further reacts with electrolyte. The unstable electrode-electrolyte interface and gradual consumption of electrolyte lead to poor electrochemical performance. Aiming at these problems, this thesis focuses on the structural design of three-dimensional (3D) current collector, artificial protective layer and optimization of solvation structure to regulate the lithium nucleation and growth behavior from bottom to top and retard dendrite growth, which thereby improved the electrochemical performance of lithium metal anodes. The main research perspectives and related achievements are summarized as follows: (1) It is revealed that in-situ growth of lithiophilic copper oxide nanosheets array on the commercial copper foil enables uniform lithium nucleation and deposition. The nucleation overpotential was largely reduced due to the lithiophilic nature of copper oxide, Moreover, the vertically aligned structure not only reduced the local current density, but also uniformed the distribution of electrical field, contributing to improved Coulombic efficiency and cycle stability of lithium metal anodes. (2) Phosphidizing the lightweight copper nanowire current collector with a gradient was proposed to realize the uniform and dense lithium deposition inside the collector. It is revealed that the lithium phosphide layer with a gradient was formed after an electrochemical reaction that guaranteed the fast transport of ions and electrons at the inner space of the 3D collector. Therefore, the high gravimetric and volumetric capacities of 1702.9 mA h/g and 1582 mA h/cm3 can be achieved, which are promising to realize high-energy-density lithium metal anodes. (3) A two-dimensional (2D) organic-inorganic hybrid material with layered structure was developed as a protective layer on the lithium surface. It is revealed that the pre-desolvation process plays an important role in the electrochemical reversibility of lithium metal. The 2D layered material with sub-nanometer channels can sieve out solvent molecules in advance, so that the side reactions between lithium and solvent molecules are prevented, accounting for the improved Coulombic efficiency (94 %) of lithium metal anodes cycled in ester-based electrolyte. (4) A non-flammable localized high concentration electrolyte was designed to improve the electrochemical performance and safety of lithium metal anodes. Introducing the flame-retardant diluent into a concentrated ether-based electrolyte makes anions dominate the primary solvation sheath of Li ions, which helps form a thin, stable and uniform solid-electrolyte interphase. Therefore, the energy barriers of desolvation and the electrochemical reaction were effectively reduced. Thus, the stability and safety of lithium metal anodes were significantly improved, and the high Coulombic efficiency of 97.8 % can be reached even at high current density of 5 mA h/cm2. Overall, based on the strategies of 3D structural design, regulation of interface reaction and electrolyte structure optimization, the stability and safety of lithium metal anodes were highly improved for promoting the development of high-energy-density lithium metal batteries.