An Air-Stable Densely Packed Phosphorene–Graphene Composite Toward Advanced Lithium Storage Properties

Phosphorene, monolayer or few-layer black phosphorus (BP), has recently triggered strong scientific interest for lithium/sodium ion batteries (LIBs/SIBs) applications. However, there are still challenges regarding large-scale fabrication, poor air stability. Herein, we report the high-yield synthesis of phosphorene with good crystallinity and tunable size distributions via liquid-phase exfoliation of bulk BP in formamide. Afterwards, a densely packed phosphorene–graphene composite (PG-SPS, a packing density of 0.6 g cm⁻³) is prepared by a simple and easily up-scalable spark plasma sintering (SPS) process. When working as anode materials of LIBs, PG-SPS exhibit much improved first-cycle Coloumbic efficiency (60.2%) compared to phosphorene (11.5%) and loosely stacked phosphorene–graphene composite (34.3%), high specific capacity (1306.7 mAh g⁻¹) and volumetric capacity (256.4 mAh cm⁻³), good rate capabilities (e.g., 415.0 mAh g⁻¹ at 10 A g⁻¹) as well as outstanding long-term cycling life (91.9% retention after 800 cycles at 10 A g⁻¹). Importantly, excellent air stability of PG-SPS over the 60 days observation in maintaining its high Li storage properties can be achieved. On the contrary, 95.2% of BP in PG sample was oxidized after only 10 days exposure to ambience, leading to severe degradation of electrochemical properties.