| Abstrakt: |
To improve the ionic conductivity of the LiFePO4cathode for high-performance solid-state lithium-ion batteries, we incorporated the chemically stable and ion-conductive Li6.75La3Zr1.75Ta0.25O12(LLZTO) into the cathode. We discovered that the impact of this incorporation on enhancing conductivity was influenced by how well the LLZTO particles were dispersed. A solid-state battery constructed with the LiFePO4cathode without any LLZTO incorporated exhibited an initial capacity of 146 mAh g−1at 0.2C, with a retention of 26 % after 100 cycles of charge-discharge. When the cathode was incorporated with LLZTO particles in their original agglomerated state, the initial capacity remained similar to the pristine one, but the retention decreased to <20 %. However, when LLZTO was well-dispersed during incorporation, the initial capacity increased to 160 mAh g−1, and retention improved to over 95 %. The difference in the effectiveness of incorporating dispersed and agglomerated LLZTO on the electrochemical performance has been clarified to be mainly related to the polarization of Li+during transport in the cathodes. This was elucidated by numerical simulations based on finite element analysis, which revealed that incorporating LLZTO agglomerates leads to a deficiency of Li+transport in specific regions within the LiFePO4cathode and non-uniform Li+transport through LLZTO, resulting in reduced overall cathode conductivity and battery performance. |
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