Abstract Non-woven mats constructed from carbon nanofibers with metal (Pt, Co, or Pd) nanoparticles on their surfaces (CNF@metal) were fabricated by coaxial electrospinning for use in non-aqueous lithium‒oxygen (Li‒O2) battery (LOB) cathodes. Through coaxial electrospinning, the metal nanoparticles were evenly distributed on the CNF surfaces, and the samples were directly applied as LOB cathodes. Although the Co and Pd nanoparticles did not promote the desired Li‒O2 reactions, the CNF@Pt exhibited much improved electrochemical performance with highly reversible Li‒O2 operations. Therefore, the Li‒O2 cell using the CNF@Pt cathode exhibited significantly enhanced specific capacity, rate capability, energy efficiency, and cycle stability compared to the other samples. The observed formation of Li2O2 film, rather than toroidal particles, on the CNF@Pt after an early stage of discharge may be attributed to greatly reduced overpotentials both on discharge and charge, as well as a considerably prolonged cycle life (163 cycles) with a limiting capacity of 1000 mAh/gc at a current density of 500 mA/gc. In particular, in-situ differential electrochemical mass spectrometry studies revealed that the cycles of the Pt-catalyzed Li‒O2 cell were mainly based on the reversible formation/decomposition of Li2O2, as evidenced by high O2 evolution and negligible CO2 evolution, even after long-term cycles.

中文翻译：

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同轴静电纺丝的碳纳米纤维@铂及其作为 Li-O 2 电池正极的电化学性能的改善

摘要 通过同轴静电纺丝法制备了由表面具有金属（Pt、Co 或 Pd）纳米颗粒的碳纳米纤维构成的无纺垫（CNF@metal），用于非水锂-氧（Li-O2）电池（LOB）。 ) 阴极。通过同轴静电纺丝，金属纳米颗粒均匀分布在CNF表面，样品直接用作LOB阴极。尽管 Co 和 Pd 纳米粒子没有促进所需的 Li-O2 反应，但 CNF@Pt 表现出大大改善的电化学性能，具有高度可逆的 Li-O2 操作。因此，与其他样品相比，使用 CNF@Pt 正极的 Li-O2 电池表现出显着增强的比容量、倍率性能、能量效率和循环稳定性。观察到形成 Li2O2 薄膜，而不是环形颗粒，在放电早期阶段后 CNF@Pt 上的显着降低可能归因于放电和充电时的过电位大大降低，以及显着延长的循环寿命（163 次循环），在电流密度为 1000 mAh/gc 时的极限容量为500 毫安/克。特别是，原位微分电化学质谱研究表明，Pt 催化的 Li-O2 电池的循环主要基于 Li2O2 的可逆形成/分解，如高 O2 析出和可忽略不计的 CO2 析出所证明，即使经过长时间-学期周期。