Bottom-top channeling Li nucleation and growth by gradient lithiophilic 3D conductive host for highly stable Li metal anodes
Li metal anode is undergoing a renaissance due to its ultra-high specific capacity and the lowest reduction potential. Yet, the practical application of Li metal anode is still challenged by Li dendrite growth and low coulombic efficiency (CE). Herein, a gradient Si-modified carbon paper (GSCP) is proposed via magnetic sputtering to address these issues, in which the content of lithiophilic Si gradually decreases from bottom to up of 3D host. Such gradient lithiophilic structure can induce Li metal selectively nucleate and grow at bottom firstly then to top part of GSCP, realizing stable Li plating/stripping and high space utilization of 3D host simultaneously. Therefore, the designed GSCP composite anode achieves average CEs of 99.0% (400 cycles) and 97.0% (150 cycles) at 1 and 5 mA cm-2, and a prolonged lifespan (1350 h) with a low overpotential (~15 mV). Remarkably, the GSCP@Li|Li4Ti5O12 full cell exhibits a high capacity retention of 84.5% after 5000 cycles at 10 C rate.
- This article is part of the themed collection: 2019 Journal of Materials Chemistry A HOT Papers