Zhao Taolin, Zhou Na, Zhang Xiaoxiao, Xue Qing, Wang Yuhua, Yang Minli, Li Li, Chen Renjie
School of Materials Science and Engineering, Shijiazhuang Tiedao University, Shijiazhuang 050043, China.
Phys Chem Chem Phys. 2017 Aug 23;19(33):22494-22501. doi: 10.1039/c7cp04092j.
Surface modification is proved to be an effective strategy to improve the power density of lithium-ion batteries (LIBs) applied in electric vehicles. In this article, a protective modification layer (FeF/LiF) is successfully deposited onto the surface of a low-cost cathode material, Li[FeNiMn]O, for realizing the improvement of ultrafast lithium storage. The reversible specific capacity and ultrahigh rate capability are effectively improved. The modified sample can achieve a higher reversible discharge specific capacity of 171.8 mA h g at 0.2C. A discharge specific capacity of 150.4 mA h g is delivered at 1C after 60 cycles. Even at 2C and 5C, the discharge specific capacities are still maintained at 135.7 and 124.5 mA h g. Notably, when charged and discharged at 20C, a discharge specific capacity of 73.4 mA h g can be achieved after 200 cycles by the heterostructured Li-Fe-Ni-Mn-O cathode, almost twice that of the bare material. The good fast lithium storage capability can be ascribed to the effective suppression of interfacial side reactions, the conversion reaction from the FeF phase, and the harmonious coexistence of layered and spinel phases. The triple benefits from the heterostructured cathode provide a promising route for constructing advanced LIBs.
表面改性被证明是提高应用于电动汽车的锂离子电池（LIBs）功率密度的有效策略。在本文中，一种保护改性层（FeF/LiF）成功沉积在低成本阴极材料Li[FeNiMn]O的表面，以实现超快锂存储性能的提升。可逆比容量和超高倍率性能得到有效提高。改性样品在0.2C时可实现171.8 mA h g的较高可逆放电比容量。60次循环后，在1C时的放电比容量为150.4 mA h g。即使在2C和5C时，放电比容量仍分别保持在135.7和124.5 mA h g。值得注意的是，对于异质结构的Li-Fe-Ni-Mn-O阴极，在20C下充放电200次后，放电比容量可达73.4 mA h g，几乎是裸材料的两倍。良好的快速锂存储性能可归因于界面副反应的有效抑制、FeF相的转化反应以及层状相和尖晶石相的和谐共存。异质结构阴极带来的这三重优势为构建先进的锂离子电池提供了一条有前景的途径。
