A Mn-Rich LiMn_0.7Fe_0.3PO₄ Nanoflower Cathode Solvothermally Synthesized with pH Control for Promoted Lithium-Ion...

Area of Science:

• Materials Science
• Electrochemistry
• Battery Technology

Background:

• Escalating demand for lithium-ion batteries necessitates cobalt- and nickel-free cathode materials due to high costs.
• LiMnₓFe₁₋ₓPO₄ (LMFP) offers high operating voltage but faces challenges with kinetics and stability.

Purpose of the Study:

• To investigate the impact of pH control on LiMn₀.₇Fe₀.₃PO₄/C microstructure and electrochemical performance.
• To elucidate the mechanism of morphology evolution influenced by pH and reaction time.

Main Methods:

• Solvothermal synthesis of LiMn₀.₇Fe₀.₃PO₄/C composites under varied pH conditions.
• Comprehensive characterization using electrochemical evaluation and structural analysis.
• Mechanism study of morphology evolution with pH and reaction duration.

Main Results:

• Optimal performance achieved at pH 4, yielding a nanoflower architecture with (010)-oriented nanosheets and graphitized carbon coating.
• The pH 4-synthesized sample (LMP/C-P4-24) exhibited high discharge capacity (151.5 mAh g⁻¹ at 1 C), excellent cycling stability (96.1% retention after 500 cycles), and rate capability (110.3 mAh g⁻¹ at 10 C).
• Higher pH values led to structural disorder, inferior carbon quality, and rapid performance degradation.

Conclusions:

• Precise pH control during solvothermal synthesis is crucial for optimizing LMFP cathode performance.
• pH-mediated structural control offers a powerful strategy for developing high-performance, resource-conscious, Mn-rich LiMn₀.₇Fe₀.₃PO₄ cathode materials.
• The findings pave the way for advanced cobalt- and nickel-free battery technologies.