TiO₂ has been explored in hybrid magnesium-lithium batteries (HMLBs) due to the advantages of low self-discharge and small volume expansion during ion insertion. However, how to improve the inherently low ionic and electrical conductivity of TiO₂ is the problem that needs to be solved. In this work, a smart strategy is adopted to prepare cobalt-doped TiO₂@C (Co⁴⁺-TiO₂@C) hierarchical nanocomposite derived from Co(II)(OH)_n@Ti₃C₂. Compared with TiO₂@C (without cobalt doping), Co⁴⁺-TiO₂@C shows the highest specific capacity (154.7 mAh·g⁻¹ at 0.1 A·g⁻¹ after 200 cycles) and extraordinary rate performance in HMLBs. The excellent electrochemical performance of Co⁴⁺-TiO₂@C is ascribed to the synergistic effect of the hierarchical structure and cobalt-doping. Both experimental results and density functional theory (DFT) calculation reveal that the cobalt-doping has effectively improved the electronic conductivity and reduced the Li⁺ migration barrier. This work provides a new insight to design TiO₂-based cathode materials with high-performance in HMLBs.

TiO ₂由于具有低自放电和离子插入过程中体积膨胀小的优点，已在混合镁锂电池（HMLB）中进行了探索。然而，如何改善TiO ₂固有的低离子电导率和电导率是亟待解决的问题。在这项工作中，采用智能策略制备钴掺杂 TiO ₂ @C (Co ⁴⁺ -TiO ₂ @C) 多级纳米复合材料，该复合材料源自 Co(II)(OH) _n @Ti ₃ C ₂。与TiO ₂ @C（无钴掺杂）相比，Co ⁴⁺ -TiO ₂ @C显示出最高的比容量（154.7 mAh·g ⁻¹ at 0.1 A·g ^{− 1} after 200 cycles) 和 HMLBs 非凡的倍率性能。Co ⁴⁺ -TiO ₂ @C优异的电化学性能归因于多级结构和钴掺杂的协同作用。实验结果和密度泛函理论（DFT）计算均表明钴掺杂有效地提高了电子电导率并降低了Li ⁺迁移势垒。这项工作为在 HMLB 中设计高性能TiO _{2基正极材料提供了新的思路。}