分级多孔钴氮掺杂碳催化剂的制备用于增强锌空气电池的耐久性

Synthesis of hierarchical porous cobalt and nitrogen-doped carbon catalysts for enhancing the durability of zinc-air batteries

  • 摘要: 开发高效且耐用的非贵金属基双功能氧电催化剂,对于实现经济高效且高性能的可充电锌空气电池(ZABs)至关重要。本研究采用独特的SiO2模版辅助原位热解和蚀刻策略,制备了具有分级多孔结构的钴氮共掺杂碳Co-100-900@SiO2催化剂。这种球形分级多孔结构独特且坚固,其介孔和大孔结构,显著改善了气体扩散电极处“固-气-液”三相界面微环境,有效平衡了反应物和产物的高效传输、活性位点可及性和结构稳定性,使该催化剂在ORR和OER方面均表现出良好的双功能催化活性。在0.1 mol/L KOH中ORR半波电位为0.799 V,极限扩散电流密度为4.3 mA·cm−2。在10 mA·cm−2的电流密度下,OER过电位为0.66 V。基于该材料构建的可充电锌空气电池,其功率密度高达155.4 mW·cm−2,以5 mA·cm−2进行1500次循环充放电后,充放电电压间隙保持在0.89 V左右,表现出卓越的耐久性。本研究成功实现了在高活性保持下稳定性的提升,为设计下一代高性能、长寿命的可充电锌空气电池提供了新思路。

     

    Abstract: The development of efficient and durable non-precious metal-based bifunctional oxygen electrocatalysts is pivotal in realizing cost-effective and high-performance rechargeable Zinc-Air Batteries (ZABs). Herein, a unique SiO2-template-assisted in-situ pyrolysis and etching strategy was employed to synthesize the Co-100-900@SiO2 catalyst, a cobalt-nitrogen co-doped carbon material with a hierarchical porous structure. This spherical hierarchical porous structure is unique and robust, its mesoporous and macroporous structures significantly improve the microenvironment at the “solid-gas-liquid” three-phase interface at the gas diffusion electrode, effectively balancing the efficient transport of reactants and products, access to active sites, and structural stability. Consequently, the catalyst exhibits excellent bifunctional catalytic activity for both ORR and OER. In 0.1 mol/L KOH, the ORR half-wave potential is 0.799 V, and the limiting diffusion current density is 4.3 mA·cm−2. At a current density of 10 mA·cm−2, the OER overpotential is 0.66 V. A rechargeable zinc-air battery constructed using this material achieved a power density as high as 155.4 mW·cm−2. After 1500 charge-discharge cycles at a current density of 5 mA·cm−2, the voltage gap remained around 0.89 V, demonstrating exceptional durability. This study successfully achieved improved stability while maintaining high activity, providing new insights for the design of next-generation high-performance, long-life rechargeable zinc-air batteries.

     

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