Preparation and design of carbon fibers reinforced carbon composite materials used as saggars for synthesizing LiFePO4 cathode materials

In this work, the carbon composites were first produced using low-cost electrically calcined anthracite and resource-utilized waste graphite electrode fine powders as raw materials. The strength and toughness of the composite materials were enhanced by introducing carbon fibers as a reinforced phase. The influences of the addition of carbon fibers on the properties of the samples were investigated. The thermal shock stability of the samples was evaluated by the water rapid cooling method, and the LiFePO 4 (LFP) corrosion resistance of the samples was examined using the static crucible method. The results exhibited that the sample (CF-0.15) with 0.15 wt% carbon fiber addition performed favorable physical properties and optimum mechanical strength. Its apparent porosity was 12.10 %, cold modulus of rupture (CMOR) was 11.95 MPa, cold crushing strength (CCS) was 33.37 MPa, and fracture toughness was 697.67 kPa m 1/2 . The residual cold modulus of rupture of CF-0.15 sample was 10.08 MPa and the residual strength ratio was 84.42 % after three thermal shocks at 1000 °C. The presence of carbon fibers provided bridging and pull-out effects, which improved the strength and toughness of the samples. This promotes the dispersion and absorption of thermal stresses in the samples during cycle thermal shock, resulting in the deflection of internal cracks to prevent further damage. The samples presented excellent corrosion resistance in the LFP erosion experiments, demonstrating significant potential to facilitate the development of the lithium battery industry.