Presentation Title: Preparation of high-density lithium iron phosphate with Nb, Ti, V co-doping and non-uniform particle distribution

Abstract: 

     This study successfully prepared high-density LiFePO4/C composite materials using a ternary co-doping strategy of Nb2O5, TiO2, and V2O5, combined with particle size optimization and control techniques. The substitution of Nb⁵⁺ for Li⁺ positions can widen the diffusion channels for Li⁺ and enhance its diffusion kinetics. The replacement of Fe²⁺ by Ti⁴⁺ can stabilize the crystal structure, reduce volume changes during charge-discharge processes, and improve cycling stability. The substitution of Fe²⁺ by V4⁺ and the introduction of electron defects can increase electronic conductivity. The synergistic co-doping of Nb⁵⁺, Ti⁴⁺, and V4⁺ increased the electrical conductivity of the LFP material from 2.0×10−1 to 2.6×10−1 S cm−1 and the Li⁺ diffusion coefficient from 7.65×10−13 to 2.39×10−12 cm2 s −1 . Moreover, by optimizing the particle size distribution and adopting a non-uniform particle grading strategy, small particles can efficiently fill the gaps between large particles, reducing porosity and further increasing the compaction density. The final Li₀.₉₉₀Nb₀.₀₁₀Fe₀.₉₉₀Ti₀.₀₀₅V₀.₀₀₅PO₄ material achieved an industry-leading compaction density of 2.72 g cm−3 under a pressure of 226 MPa. lectrochemical tests showed that the discharge capacities at 0.2 C and 5 C rates were 166.2 mAh g−1 and 142.4 mAh g−1 , respectively, and the capacity retention rate after 1000 cycles at 5 C was 91.34%. The assembled 14,500 cylindrical battery exhibited excellent volumetric energy density (0.2 C: 1166.27 Wh L−1 , 1 C: 1109.62 Wh L−1 ).

Biography: 

      Liang Guangchuan, Professor and Doctoral Supervisor，Director of the Institute of Energy and Environmental Protection Materials at Hebei University of Technology. He has been honored with titles such as Taishan Industrial Leading Talent of Shandong Province, Hebei Province's New Century "333" Talent Program recipient, and Hebei Province's Outstanding Postdoctoral Fellow. He also serves as the Director of the Academic Committee of the Shandong Provincial Energy Storage Battery Technology Innovation Center. For many years, he has been engaged in research on new energy and materials, having led projects including key special programs of the Ministry of Science and Technology of China and the National "863" Program. He has received 8 provincial and ministerial-level scientific and technological awards, published over 100 high-impact papers indexed in SCI, obtained more than 100 patents, and authored 6 monographs.