Unveiling the electrochemical behavior of lithium manganese phosphate crystallized glass cathodes for energy storage technologies

Abstract

Escalating global demand for eco-conscious energy storage systems has intensified research efforts toward cutting-edge electrodes for lithium-ion batteries (LIBs). Phosphate-based glasses and their crystallized derivatives (glass-ceramics) have made them attractive options due to their tunable electrochemical characteristics, structural stability, and cost-effectiveness. This study inspects how controlled crystallization affects the performance of a 15Li₂O–30MnO₂–55P₂O₅ (LMP-glass) as a cathode material for LIBs. The LMP-glass was synthesized via melt-quenching and subsequently heat-treated to produce glass-ceramics (LMP-HT2h and LMP-HT5h) with nanocrystalline Mn₃(PO₄)₂, Li₂MnP₂O₇ and Mn(PO₃)₂ crystalline phases. Structural characterization via XRD, FTIR, and TEM confirmed the formation of crystalline domains (71–94 nm) embedded in a residual glassy matrix, enhancing ionic conductivity and mechanical stability. Electrochemical evaluations revealed that the LMP-HT5h electrode delivered a high discharge capacity of 256 mAh g⁻¹ at 30 mA g⁻¹, with 86.3 % capacity retention over 100 cycles, outperforming the pristine glass electrode (9.8 % retention). The crystallized samples exhibited superior rate capability (71.9 % capacity retention at 100 mA g⁻¹) and lower polarization, attributed to the synergistic effects of nanocrystalline pathways for Li⁺ diffusion and the buffering role of the amorphous phase. These presented findings demonstrate the promise of phosphate-based glass-ceramics as high-performance, environmentally benign cathodes for next-generation LIBs, addressing critical challenges in energy density and cycling stability.