National Laboratory of Solid State Microstructures, College of Engineering and Applied Sciences and Collaborative Innovation Center of Advanced Microstructures , Nanjing University , Nanjing 210093 , China.
Research Center for Environmental Nanotechnology (ReCENT) , Nanjing University , Nanjing 210023 , China.
ACS Appl Mater Interfaces. 2018 Apr 18;10(15):12750-12758. doi: 10.1021/acsami.8b02150. Epub 2018 Apr 5.
Developing new electrode materials with high capacity and stability is an urgent demand in electric vehicle applications. Li Si alloy, as a promising high-capacity and Li-containing anode candidate, has attracted much attention. However, the alloy anode suffers severely from intrinsic high chemical reactivity and poor cycling stability in battery fabrication and operation. Here, we have developed a facile coating-then-lithiation approach to prepare lithiated-TiO protected Li Si nanoparticles (Li Si-LiO/Ti O NPs) as an attractive anode material. The robust lithiated-TiO protection matrix not only provides fast electron transport pathways to efficiently improve the electrical conductivity between Li Si/Si NPs, but also spatially limits the direct solid electrolyte interphase formation on Li Si/Si cores during cycling. More importantly, this dense coating layer protects most inner Li Si alloys from ambient corrosion, leading to high dry-air stability. As a result, the resulting Li Si-LiO/Ti O anode achieves greatly enhanced cycling and chemical stability in half-cells. It maintains capacity of about 1300 mAh g after prolonged 500 cycles at a high current rate of C/2, with 77% capacity retention. In addition, it exhibits excellent dry-air stability, with around 87% capacity retained after exposure to dry air (10% relative humidity) for 30 days.
开发具有高容量和稳定性的新型电极材料是电动汽车应用中的迫切需求。硅合金作为一种很有前途的高容量含锂阳极候选材料，引起了广泛关注。然而，合金阳极在电池制造和使用过程中存在严重的固有高化学反应性和较差的循环稳定性问题。在这里，我们开发了一种简便的包覆-锂化方法，制备了具有保护性的锂化 TiO 的 Li Si 纳米颗粒（Li Si-LiO/Ti O NPs），作为一种有吸引力的阳极材料。坚固的锂化 TiO 保护层不仅提供了快速的电子传输途径，有效地提高了 Li Si/Si NPs 之间的导电性，而且在循环过程中空间上限制了直接固体电解质相间在 Li Si/Si 核上的形成。更重要的是，这种致密的包覆层保护了大多数内部 Li Si 合金免受环境腐蚀，从而提高了干燥空气稳定性。因此，所得的 Li Si-LiO/Ti O 阳极在半电池中表现出极大地增强的循环和化学稳定性。它在高电流速率 C/2 下经过 500 次循环后，仍能保持约 1300 mAh g 的容量，容量保持率为 77%。此外，它还表现出出色的干燥空气稳定性，在暴露于干燥空气（相对湿度为 10%）30 天后，容量保持率约为 87%。
