Ultrathin Few‐Layer GeP Nanosheets via Lithiation‐Assisted Chemical Exfoliation and Their Application in Sodium Storage

Abstract Ultrathin few‐layer materials have attracted intensive research attention because of their distinctive and unique properties. Few‐layer GeP (FL‐GP) is potentially interesting for application in electronics and optoelectronics because of its appropriate band gap and good stability under ambient conditions. Nevertheless, it is a challenge to achieve ultrathin few‐layer or single layer GeP from exfoliation of bulk crystals. Here, a lithiation‐assisted chemical exfoliation technique is employed to achieve FL‐GP, in which the interlayer spacing can be efficiently enlarged after a preliminary lithium ion intercalation, allowing the bulk crystal to be readily exfoliated in a following ultrasonication. As a result, ultrathin FL‐GP is obtained. In a demonstration, the FL‐GP/reduced graphene oxide (rGO) demonstrates remarkable sodium storage performance. The FL‐GP with a two‐dimensional structure shortens the ion transport pathways and alleviates the volume variation during sodiation. Meanwhile, the rGO in the composite improves the conductivity of the whole electrode. The as‐prepared FL‐GP/rGO electrode exhibits a high capacity of 504.2 mAh g⁻¹ at 100 mA g⁻¹, remarkable rate performance, and superior cycling stability in the half cells. FL‐GP/rGO//Na₃V₂(PO₄)₃ full cells are also assembled and demonstrated satisfactory electrochemical performance, indicating potential application of the as‐prepared anode materials.