锂氧电池高容量正极材料花球状碳微球的三维复刻构筑（英文）

Ball-flower-like carbon microspheres via a three-dimensional replication strategy as a high-capacity cathode in lithium–oxygen batteries

活性物质和电极的多孔结构设计是实现锂氧电池中氧气电极高容量和良好可逆性的关键措施.本文报道了一种创新的三维复刻策略,并用于设计锂氧电池氧气电极用多孔碳材料的三维结构.作为一个实例,采用聚多巴胺包覆层为碳源,通过完整复制纳米结构氧化锌模板的形貌,成功地制备了由扭曲的中空碳纳米片组装而成的花球状碳微球.作为氧气电极的活性物质,花球状碳微球的三维多孔结构不仅能容纳放电产物过氧化锂,同时也能保持离子和气体的扩散通道.此外,氮掺杂引入的高缺陷为氧还原/析出反应提供了充足的活性位点.从而,花球状碳微球表现出高达9163.7 mA h g^(-1)的比容量和优异的可逆性.本工作呈现了一种用于能源存储和转化的多孔碳材料的三维结构的有效可控制备方法,即复制过渡金属氧化物模板的纳米结构.

The robust porous architectures of active materials are highly desired for oxygen electrodes in lithium–oxygen batteries to enable high capacities and excellent reversibility. Herein, we report a novel three-dimensional replication strategy to fabricate three-dimensional architecture of porous carbon for oxygen electrodes in lithium–oxygen batteries. As a demonstration, ball-flower-like carbon microspheres assembled with tortuous hollow carbon nanosheets are successfully prepared by completely replicating the morphology of the nanostructured zinc oxide template and utilizing the polydopamine coating layer as the carbon source.When used as the active material for oxygen electrodes, the three-dimensional porous architecture of the prepared ballflower-like carbon microspheres can accommodate the discharge product lithium peroxide and simultaneously maintain the ions and gas diffusion paths. Moreover, their high degrees of defectiveness by nitrogen doping provide sufficient active sites for oxygen reduction/evolution reaction.Thus the prepared ball-flower-like carbon microspheres demonstrate a high capacity of 9,163.7 mA h g-1 and excellent reversibility. This work presents an effective way to prepare three-dimensional architectures of porous carbon by replicating the controllable nanostructures of transition metal oxide templates for energy storage and conversion applications.