Dendrite-free lithium deposition enabled by a vertically aligned graphene pillar architecture.

Uncontrollable dendrite growth and poor reversibility of lithium (Li) metal anode hinder the practical implementation of Li metal based batteries. Herein, we report a feasible and scalable electrospraying strategy for fabricating a vertically aligned graphene (VAG) pillar architecture with low tortuosity and high specific surface area as both current collector and host material for Li metal anode. Columnar and dense Li with large granular size plates into the VAG electrode by the aid of the pillar structure, which could ensure continuous ion transfer and lower actual current density for uniform nucleation, as well as provide more accommodation with proper space size. The hollow graphene pillars and the surrounding sufficient space enables smooth Li plating under high capacity depth and abstains volume fluctuation of the whole electrode. The VAG pillar modified Li anode delivers low overpotential of 25 mV over 280 h under a high rate of 3 mA cm−2, and high Coulombic efficiencies for 250 cycles at a capacity of 1 mAh cm−2. More importantly, full cells paired with the high capacity LiFePO 4 cathode exhibit excellent cycling stability and rate capability, demonstrating the high Li utilization efficiency and improved ion migration kinetic in the low tortuous VAG architecture. A lightweight vertically aligned graphene (VAG) architecture consisting of open channels and vertical graphene pillars is developed by a facile and scalable method. The low tortuosity, large specific surface area of VAG architecture contribute to dendrite-free Li plating behavior and continuous ion-transport pathways, thus significantly enhancing the reversibility of anode. [Display omitted] • A vertically aligned graphene (VAG) architecture with low tortuosity is developed. • The VAG architecture consists of hollow graphene pillar and appropriate interspace. • Uniform and columnar Li deposits are realized into internal space of VAG electrode. • The reversibility of VAG-modified anode is thus significantly improved. [ABSTRACT FROM AUTHOR]