Hard template synthesis of Zn, Co co-doping hierarchical porous carbon framework for stable Li metal anodes

Abstract

Li metal is regarded as the most potential anode material due to the high energy density, low redox potential and high theoretical specific capacity. However, the development of the Li metal battery is seriously restricted by dendrite and huge volume change. In this paper, a hierarchical porous carbon framework with Zn/Co co-doping (PACF-ZC) is prepared by hard template method. Due to the combined action of different porous structures, the interior space provides sufficient reduction place for Li+ plating, when the Li+ flux uniformly disperses on the surface of PACF-ZC. So, the huge volume and growth of dendritic Li can be repressed by the distinctive hierarchical porous structure, effectively. In addition, the co-doping of Zn and Co reduces the nucleation barrier and promotes the Li affinity of PACF-ZC. The pyridine N and pyrrolidine N in precursor can optimize the behavior of Li+ plating. Benefit from the synergistic effect of hierarchical porous structure and Zn, Co co-doping, the symmetrical battery with Li@PACF-ZC obtains an ultra-long cycle life (1800 h) at 1 mA cm−2 with a capacity of 1 mAh cm−2. Meanwhile, the full cell of Li@PACF-ZC||LiFePO4 yields a high specific capacity of 128.8 mAh/g under 1C after 100 cycles.