The uneven lithium deposition on Cu current collector and poor interface stability of lithium metal/electrolyte would lead to rapid capacity decay and potential safety risks, which severely hinder the practical applications of lithium metal batteries. In this work, the in-situ derived Ti3C2Tx MXene/TiO2 (labeled as MXene/TiO2) composite with favorable lithiophilicity and conductivity is applied as modified layer on Cu foil current collector (labeled as MXene/TiO2@Cu) to obtain the uniform and dense lithium plating. Compared with bare Cu and commercial TiO2 nanoparticles modified Cu current collector (labeled as Nano TiO2@Cu), the MXene/TiO2@Cu combines abundant lithium nucleation sites and improved conductivity, which could promote uniform lithium plating and stripping at high current density and effectively avoid the generation of dead lithium or lithium dendrites. As a result, the MXene/TiO2@Cu-based symmetric battery could stably cycle for 2000 h at high current density of 3 mA cm−2 with capacity of 3 mAh cm−2, and the MXene/TiO2@Cu-Li‖LiFePO4 full battery could maintain the high reversible capacity of 104.0 mAh g−1 at 1 C after 500 cycles. This work provides an effective and novel protection strategy for Cu current collector, which is critical for the design of lithium metal batteries with favorite rate capability at high current density.

中文翻译：

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原位衍生的 Ti3C2TX MXene/TiO2 改性铜箔结合了丰富的成核位点和良好的导电性，可实现稳定的锂金属电池


Cu集流体上锂沉积不均匀以及锂金属/电解质界面稳定性差会导致容量快速衰减和潜在的安全风险，严重阻碍了锂金属电池的实际应用。在这项工作中，原位衍生的Ti3C2TX MXene/TiO2（标记为MXene/TiO2）复合材料具有良好的亲锂性和导电性，作为修饰层应用于铜箔集流体（标记为MXene/TiO2@Cu）上，以获得均匀和致密的锂镀层。与裸铜和商用TiO2纳米颗粒改性铜集流体（标记为Nano TiO2@Cu）相比，MXene/TiO2@Cu结合了丰富的锂成核位点和改进的电导率，可以在高电流密度下促进均匀的锂沉积和剥离，并有效地促进锂的沉积和剥离。避免产生死锂或锂枝晶。结果表明，MXene/TiO2@Cu基对称电池可以在3 mA cm−2的高电流密度下稳定循环2000 h，容量为3 mAh cm−2，并且MXene/TiO2@Cu-Li‖LiFePO4全电池在1C下循环500次后仍能保持104.0mAh g−1的高可逆容量。这项工作为铜集流体提供了一种有效且新颖的保护策略，这对于设计在高电流密度下具有最佳倍率性能的锂金属电池至关重要。