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<p>Cobalt-free lithium-rich manganese-based materials have emerged as one of the most promising cathode materials due to their inexpensive cost, high specific capacity, strong durability, and low toxicity. However, “cobalt-free” materials often cause transition metal dissolution and lithium-nickel mixing, resulting in a number of serious problems that hinder their commercialization. By taking into account the precursors, this work sought to create a reasonable particle structure design that includes heterogeneous nucleation of precursors and uniform phase transitions during lithiation, thereby reducing structural phase transitions during cycling and improving the electrochemical performance of LMOs. The results indicate that, the modified cathode materials have exceptional cycling life and superior lithium-ion migration characteristics. Compared to original materials Li<sub>1.2</sub>Mn<sub>0.6</sub>Ni<sub>0.2</sub>O<sub>2</sub> (242.71 mAh g<sup>− 1</sup>), the reversible specific capacities of the modified materials Li<sub>1.2</sub>Mn<sub>0.6</sub>Ni<sub>0.2</sub>O<sub>2</sub>&amp;Nb and Li<sub>1.2</sub>Mn<sub>0.6</sub>Ni<sub>0.2</sub>O<sub>2</sub>&amp;Li<sub>3</sub>NbO<sub>4</sub> have risen to 287.88 mAh g<sup>− 1</sup> and 297.18 mAh g<sup>− 1</sup>, respectively. And the coulombic efficiencies have increased, going from 65.28 to 72.59% and 80.99%. After 200 charge-discharge cycles at a current density of 250 mA g<sup>− 1</sup>, the Li<sub>1.2</sub>Mn<sub>0.6</sub>Ni<sub>0.2</sub>O<sub>2</sub>&amp;Nb<sub>2</sub>O<sub>5</sub> exhibits 98% the capacity retention rate, with a discharge specific capacity still at 230 mAh g<sup>− 1</sup>, while the discharge capacity of Li<sub>1.2</sub>Mn<sub>0.6</sub>Ni<sub>0.2</sub>O<sub>2</sub>&amp;Li<sub>3</sub>NbO<sub>4</sub> slightly increases during the first 150 cycles. Additionally, further evidence indicates that the modified material enhances lithium-ion diffusion capabilities, derived from Galvanostatic Intermittent Titration Technique, various scan rate of Cyclic Voltammetry, and Electrochemical Impedance Spectroscopy tests.</p> Graphical abstract <p></p>

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Enhancing the performance of Co-free lithium-rich manganese-based materials via heterogeneous nucleation of precursors

  • 期刊论文

  • 发表日期：

    2025年8月5日

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  • Longxing Xie,
  • Wei Hu,
  • Boyuan Wang,
  • Chenchen Sun,
  • Haofeng Tan,
  • Qian Zhang,
  • Quanxin Ma

摘要

Cobalt-free lithium-rich manganese-based materials have emerged as one of the most promising cathode materials due to their inexpensive cost, high specific capacity, strong durability, and low toxicity. However, “cobalt-free” materials often cause transition metal dissolution and lithium-nickel mixing, resulting in a number of serious problems that hinder their commercialization. By taking into account the precursors, this work sought to create a reasonable particle structure design that includes heterogeneous nucleation of precursors and uniform phase transitions during lithiation, thereby reducing structural phase transitions during cycling and improving the electrochemical performance of LMOs. The results indicate that, the modified cathode materials have exceptional cycling life and superior lithium-ion migration characteristics. Compared to original materials Li1.2Mn0.6Ni0.2O2 (242.71 mAh g− 1), the reversible specific capacities of the modified materials Li1.2Mn0.6Ni0.2O2&Nb and Li1.2Mn0.6Ni0.2O2&Li3NbO4 have risen to 287.88 mAh g− 1 and 297.18 mAh g− 1, respectively. And the coulombic efficiencies have increased, going from 65.28 to 72.59% and 80.99%. After 200 charge-discharge cycles at a current density of 250 mA g− 1, the Li1.2Mn0.6Ni0.2O2&Nb2O5 exhibits 98% the capacity retention rate, with a discharge specific capacity still at 230 mAh g− 1, while the discharge capacity of Li1.2Mn0.6Ni0.2O2&Li3NbO4 slightly increases during the first 150 cycles. Additionally, further evidence indicates that the modified material enhances lithium-ion diffusion capabilities, derived from Galvanostatic Intermittent Titration Technique, various scan rate of Cyclic Voltammetry, and Electrochemical Impedance Spectroscopy tests.

Graphical abstract