Nano-Li4Ti5O12 particles in-situ deposited on compact holey-graphene framework for high volumetric power capability of lithium ion battery anode
Abstract
It is still a considerable challenge for spinel Li4Ti5O12 to achieve high tap density while retaining excellent power capability. Herein, a compact and mesopore-oriented holey-graphene framework (HGF) caging nano-Li4Ti5O12 particles (Li4Ti5O12/HGF) is synthesized by capillary shrink effect. In the capillary drying process, nano-Li4Ti5O12 particles prevent the absolute aggregation of graphene sheets, remaining mesopore-oriented porosity for rapid Li+ diffusion. After precisely adjusting the porous structure, Li4Ti5O12/HGF composite successfully achieves a balance between tap density and porosity. Furthermore, the in-plane nanopores of holey-graphene sheets provide channels for Li+ diffusion, obviously weakening the Li+ diffusion resistances of compact composite. The resultant Li4Ti5O12/HGF composite combines a high tap density of 1.1 g cm-3 and a moderate mesopore-oriented porosity with BET specific area of 152 m2 g-1, delivering volumetric-specific capacities of 161, 142, 120, 103 mA h cm-3 at 0.035, 1.75, 7 and 14 A g-1, respectively. Even as current density reaches 17.5 A g-1, the as-prepared Li4Ti5O12/HGF composite still displays a capacity of 98 mA h cm-3, showing excellent ultrahigh-rate performance. After 1000 cycles at 7A g-1, the capacity of dense Li4Ti5O12/HGF composite remains 84%, demonstrating high cycle stability.
- Publication:
-
Journal of Power Sources
- Pub Date:
- January 2020
- DOI:
- 10.1016/j.jpowsour.2019.227372
- Bibcode:
- 2020JPS...44727372X
- Keywords:
-
- Volumetric high-rate capability;
- Mesopore-oriented porosity;
- Compact holey-graphene network;
- Nanosized Li<SUB>4</SUB>Ti<SUB>5</SUB>O<SUB>12</SUB> particles;
- Capillary evaporation drying effect