2026 Undergraduate Poster Award

Dispersant blending strategy for concentrated LiMnxFe1-xPO4 electrode slurries

Seong Lee | Seoul National University
Cheolheon Hyun | Seoul National University
Woohyeon Jo | Seoul National University
Jaewook Nam, PhD | Seoul National University

Abstract

LiMn_xFe_1-xPO₄ (LMFP) is a promising cathode material offering high energy density and cost competitiveness. However, its intrinsic properties promote severe particle agglomeration, which elevates viscosity and induces gel-like behavior in concentrated slurries, hindering uniform coating. Polyvinylpyrrolidone (PVP) effectively disperses the agglomerates, but acts as an insulating layer at the LMFP interface, degrading electrochemical performance with increasing content. To mitigate this trade-off between slurry dispersion and electrochemical performance, we present a blending strategy based on the molecular-weight-dependent dispersion mechanism of PVP. Model suspensions containing either LMFP or the conductive additive (CA) alone reveal that low-molecular-weight PVP directly adsorbs onto both components, whereas high-molecular-weight PVP preferentially adsorbs onto CA. In LMFP-only suspensions, the long chains bridge particles rather than dispersing them, forming a system-spanning network with a low power-law exponent of the storage modulus and slow recovery. Guided by this selectivity, the addition sequence during slurry mixing directs each chain length to its preferred surface: long chains during the CA dispersion step, short chains upon LMFP addition, at a total content of only 0.125 wt%. The blended slurry shows the most pronounced shear thinning of all compositions, suppressing particle settling at rest while easing the coating flow, and achieves dispersion comparable to that of 0.5 wt% single high-molecular-weight PVP at one-quarter of the content. The cell with blended PVP delivers 129 mAh/g at 1C against 135 mAh/g without PVP and a higher capacity after 100 cycles, 83 against 66 mAh/g. These results show that understanding the dispersion mechanism can guide dispersant selection and the addition sequence in slurry prepration for high-solid-content LMFP electrodes.

Undergraduate Prize, 97^th Annual Meeting, Oct 2026, Boston