Recent Advances in Lithium Ion/Lithium Metal Hybrid Anodes: from Design Principles to Practical Applications

Lithium metal is widely regarded as the ultimate anode material for next-generation high-energy-density batteries due to its exceptional theoretical specific capacity (3860 mA h g^-1) and low redox potential (-3.04 V vs standard hydrogen electrode). However, its practical application is hindered by low Coulombic efficiency, rapid capacity degradation, and severe safety risks caused by uncontrolled dendrite growth, substantial volume variations, and unstable solid electrolyte interphase formation. To address these limitations, an emerging paradigm involves the strategic integration of lithium metal with porous graphite or graphitized carbon hosts, forming lithium-ion/lithium-metal hybrid anodes. Such hybrid architectures utilize the synergistic advantages of both materials: graphite provides a mechanically robust, conductive framework with a well-defined structure to regulate Li plating/stripping processes, while Li metal delivers unparalleled capacity. This review systematically summarizes recent breakthroughs in mechanistic understanding, configuration designs, and electrolyte engineering that optimize the performance of hybrid anodes for high-energy lithium metal batteries. A critical analysis of the interfacial stabilization and the influence of electrolyte composition in improving cycling stability is conducted. Finally, a concise conclusion and prospective outlook regarding current challenges and future research opportunities in the material design and the development of compatible electrolyte systems of hybrid anode systems are proposed.