<p>Commercial negative electrodes such as graphite and Li<sub>4</sub>Ti<sub>5</sub>O<sub>12</sub> are fundamental to lithium-ion batteries but face inherent trade-offs among safety, energy density, rate performance, and cycling stability. In this work, we introduce structural ordering and vacancy engineering into a perovskite negative electrode Ce<sub>2/3</sub>TiO<sub>3</sub> to tackle this dilemma, by creating highly ordered Ce vacancies that form a stable superlattice. As a result, micron-sized Ce<sub>2/3</sub>TiO<sub>3</sub> achieves a high specific capacity (&gt;200 mAh g<sup>-1</sup>) at an optimal operating potential (~0.8 V vs. Li<sup>+</sup>/Li), with fast-charging capability up to 50 C and stable cycling performance exceeding 10000 cycles at 20 C. Its electrochemical performance has the potential to overcome the shortcomings of graphite and Li<sub>4</sub>Ti<sub>5</sub>O<sub>12</sub>, comparable to many representative intercalation-type negative electrodes. In situ structural analysis and atomic-scale imaging reveal a reversible topological phase transition between long-range and short-range ordering, which preserves the lattice integrity while unlocking low-barrier Li<sup>+</sup> diffusion pathways. Here, we show that vacancy ordering provides a compelling strategy for designing high-performance electrodes.</p>

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Vacancy-ordered perovskite superlattice in cerium titanate negative electrode for enhanced lithium-ion storage

  • Xuhui Xiong,
  • Zhengwang Liu,
  • Ruixuan Zhang,
  • Liting Yang,
  • Guisheng Liang,
  • Ke Pei,
  • Renchao Che

摘要

Commercial negative electrodes such as graphite and Li4Ti5O12 are fundamental to lithium-ion batteries but face inherent trade-offs among safety, energy density, rate performance, and cycling stability. In this work, we introduce structural ordering and vacancy engineering into a perovskite negative electrode Ce2/3TiO3 to tackle this dilemma, by creating highly ordered Ce vacancies that form a stable superlattice. As a result, micron-sized Ce2/3TiO3 achieves a high specific capacity (>200 mAh g-1) at an optimal operating potential (~0.8 V vs. Li+/Li), with fast-charging capability up to 50 C and stable cycling performance exceeding 10000 cycles at 20 C. Its electrochemical performance has the potential to overcome the shortcomings of graphite and Li4Ti5O12, comparable to many representative intercalation-type negative electrodes. In situ structural analysis and atomic-scale imaging reveal a reversible topological phase transition between long-range and short-range ordering, which preserves the lattice integrity while unlocking low-barrier Li+ diffusion pathways. Here, we show that vacancy ordering provides a compelling strategy for designing high-performance electrodes.