Facile synthesis of amorphous Cr₂O₃/N‐doped carbon nanosheets and its excellent lithium storage property

Abstract

The Cr2O3 with high‐energy density and relatively low lithium insertion potential is a promising anode candidate for LIBs. However, the intrinsic poor electroconductivity and side effects like volume expansion of Cr2O3 severely limit its capacity and cyclability at high charge/discharge rates. To address the problem, the amorphous Cr2O3/N‐doped carbon nanosheets (denoted as a‐Cr2O3/NC) have been designed and prepared by an easy one‐step solution combustion synthesis method from a uniform solution of chromium nitrate, glucose, and glycine. The as‐synthesized a‐Cr2O3/NC consist of amorphous Cr2O3 particles and N‐doped carbon sheet, where the amorphous Cr2O3 is evenly encapsulated in the carbon sheet support. An anode prepared from the synthesized a‐Cr2O3/NC demonstrates much higher specific capacity and better cycling performance than the crystalline Cr2O3 anode. Upon extended cycling, the a‐Cr2O3/NC anode exhibits good long‐term stability and its reversible capacity retains as high as 782.4 mAh g−1 after 500 cycles at 1 A g−1. Such good performance stems from its unique structure. The amorphous structure of Cr2O3 can furnish a mass of enterable active sites which can favor the lithium ions insertion/extraction, whereas the sheet‐like N‐doped carbon support can increase the electroconductivity and facilitate the transportation of lithium ions and electrons.