LiFePO₄ nanoplates with {010} exposed active planes prepared by hydrothermal method

It is well known that lithium-ion transport in olivine LiFePO₄ is through one-dimensional (1D) channels along the [010] direction. Therefore, the crystal structure of LiFePO₄ should be controlled to shorten Li⁺ diffusion pathway and orient {010} facets. In this work, LiFePO₄ nanoplates with preferred growth {010} active facets are synthesized by hydrothermal method in the presence of NH₄ ⁺ and ascorbic acid. The effects of organic additive on the morphologies and structures are characterized by XRD and SEM. It is recognized that organic additive plays a critical role in crystal growth in hydrothermal reaction and a rational mechanism is speculated. In addition, LiFePO₄/C is prepared by mixing procedure of LiFePO₄ nanoplates with 30 wt% ascorbic acid and carbonized at 600 °C for 5 h in Ar atmosphere. The resulting LiFePO₄/C sample is used as cathode materials for lithium-ion batteries. The electrochemical performances are evaluated by galvanostatic charge–discharge cycling tests and cyclic voltammetry. LiFePO₄/C displays a high initial discharge capacity of 163.62 mAh/g at 0.1C (1C = 170 mA/g) between 2.5 and 4.2 V.