Polypyrrole Nanotube Sponge Host for Stable Lithium-Metal Batteries under Lean Electrolyte Conditions
Wei Yao, Shijie He, Jianguang Xu, Jinshan Wang, Meng He, Qinfang Zhang, Yingliang Liu, Xu Xiao
Abstract
The key bottlenecks preventing the practical application of the lithium–metal anode in the secondary batteries are the uncontrollable growth of dendritic Li and huge volume changes during cycling, which rapidly consume the electrolyte and incur short lifespan and poor electrochemical performance. In general, the use of three-dimensional (3D) porous scaffolds with high lithiophilicity is an effective way to solve these problems. Here, we report on a dendrite-free Li-metal anode enabled by an advanced 3D polypyrrole nanotube sponge (PPy-NS) as a Li host. The pyrrolic nitrogen functional groups guide uniform Li nucleation and growth with low overpotential. The conductive 3D skeleton effectively homogenizes the local electric field and Li-ion flux, further restraining dendrite formation. Benefiting from excellent Li deposition behavior, the 3D PPy-NS delivers a high Coulombic efficiency of 98.7% over 500 cycles and ultralong lifespan (1100 h) together with low overpotential (22 mV at 1 mA cm–2). Moreover, coupled with LiNi0.8Co0.1Mn0.1O2 cathodes, Li-metal full batteries show a remarkable capacity of 3.0 mA h cm–2 with 81.5% of the initial capacity over 140 cycles at discharging rate of 0.5 C under a lean electrolyte of 7 g A h–1 and negative/positive capacity ratio of 3. This work sheds light on designing and developing advanced 3D lithiophilic hosts for stable dendrite-free Li-metal batteries.