Carbon-Phosphorus Bonds-Enriched 3D Graphene by Self-Sacrificing Black Phosphorus Nanosheets for Elevating Capacitive Lithium Storage.

Heteroatom-doping engineering has been verified as an effective strategy to tailor the electronic and chemical properties of materials. The high amount doping of nonmetal atoms to achieve desired performance, however, is always a grand challenge. Herein, a new strategy to achieve ultrahigh-level doping of phosphorus in a 3D graphene skeleton is proposed by sacrificing heterostructured two-dimensional black phosphorus on graphene. Via this approach, the phosphorus-loading in graphene hydrogel reached a record of 4.84 at. %, together with the formation of tunable pores of size 1.7-17.5 nm in graphene. During reaction kinetic analysis, the highly phosphorus-doped 3D graphene hydrogel anode exhibited more favorable capacitive-controlled ion storage behaviors, leading to a specific capacity as high as 1000 mA h g after 1700 cycles, which is superior to the pristine graphene hydrogel electrode. This simple but effective phosphorization offers an effective doping strategy for producing ultrahigh-level phosphorous doping but avoids the usual use of toxic phosphorous precursors. Furthermore, the modulation on the activation process over cycling investigated in this work gives us a new insight into designing stable anodes for carbonaceous electrode materials.