Electrochemically Exfoliated Phosphorene–Graphene Hybrid for Sodium‐Ion Batteries

Abstract

Black phosphorus, an attractive anode material for sodium‐ion batteries (SIBs), has aroused grand attention because of its high theoretical capacity. Nevertheless, its practical exploration is limited by large volume swelling, followed by rapid capacity decaying. Herein, both large‐area few‐layer phosphorene and low‐defect graphene are obtained by electrochemical exfoliation. The sandwich‐structured phosphorene–graphene hybrid with the simultaneous introduction of PC and POC bonds through chemical activation is employed to heighten the performance of SIBs, leading to a high specific capacity of 2311 mA h g−1 (based on the mass of phosphorene) at 0.1 A g−1 with a capacity retention of 83.9% after 100 loops, which can be ascribed to the flexible space of graphene layers that alleviates the volumetric expansion of phosphorene. Moreover, the stable chemical bonds as the bridge for electrons transferring can immobilize phosphorene and protect phosphorene from cracking during the sodiation/desodiation process. Expectedly, the anode exhibits excellent cycle performance of 200 loops with retained capacities of 1582.6 and 1120.6 mA h g−1 at 1 and 5 A g−1, respectively. Therefore, this electrochemical approach provides a guide for the preparation of other sandwiched 2D materials, which can be applied in high‐performance energy‐storage devices.

Emerging 2D Materials Produced via Electrochemistry

“…Moreover, it displayed an impressive cycling stability (509 mAh g −1 after 250 cycles at 1.0 A g −1 ) for sodium ion batteries. Recently, EG sheets were employed as protective layers to stabilize few‐layer phosphorene thus to increase the overall electrochemical performance ( Figure a) . The PO and POC bonds were formed in the sandwich‐structured phosphorene‐EG composite through chemical activation.…”

“…d) The rate performance of the phosphorene–graphene electrode at various current densities from 0.1 to 5 A g −1 . Reproduced with permission . Copyright 2018, Wiley‐VCH.…”

“…Recently, EG sheets were employed as protective layers to stabilize fewlayer phosphorene thus to increase the overall electrochemical per formance (Figure 8a). [111] The PO and POC bonds were formed in the sandwichstructured phosphoreneEG composite through chemical activation. With an optimal mass ratio (1:1) of phosphorene and EG, this hybrid anode material showed a specific capacity of 2311 mAh g −1 at 0.1 A g −1 for Naion storage (Figure 8b,c).…”

“…Reproduced with permission. [111] Copyright 2018, Wiley-VCH. e) Anodic etching of bulk Ti 3 AlC 2 to produce MXene.…”

2D Elemental Nanomaterials Beyond Graphene

“…Due to these unique properties, phosphorene bridges the prolonged energy gap between layered semimetal ( e. g ., graphene) and semiconducting transition‐metal dichalcogenides ( e. g ., MoS 2 and MoSe 2 ) . In addition, phosphorene is a potential anode material for batteries . The history of phosphorene dates back to 1914 when Bridgman synthesized its bulk counterpart, black phosphorus (BP) from white phosphorus .…”