Interface-coupled 1D/2D/2D CoTe2/graphene/carbon heterostructures as high-performance anode materials for potassium ion batteries

Abstract

Exploration of novel anode materials exhibiting outstanding electrochemical performances holds immense significance for the advancement of potassium-ion batteries (PIBs). In this work, interface-coupled 1D/2D/2D CoTe₂/graphene/carbon heterostructures (CoTe₂@rGO@C) were successfully synthesized via a simple one-step hydrothermal method combined with a carbonization process. The three-dimensional conductive network, synergistically constructed with graphene and nitrogen-doped carbon layers through dual physical encapsulation, not only enhanced electrical conductivity and K-ion diffusion kinetics but also effectively accommodated the volume changes of CoTe₂ nanorods, thereby maintaining the structural integrity of the electrode during cycling. Specifically, it delivered an impressive specific capacity of 182.0 mA h g⁻¹ after 400 cycles at 500 mA g⁻¹, with an exceptional rate capability of 163.8 mA h g⁻¹ at an ultrahigh current density of 5000 mA g⁻¹. Furthermore, the material exhibited outstanding cycling stability, maintaining a capacity retention of over 99.8% after 1000 cycles at 1000 mA g⁻¹. This heterogeneous engineering approach, combined with an innovative one-dimensional–two-dimensional–two-dimensional hybrid architecture, offers a promising strategy for designing novel heterostructural anode materials with exceptional electrochemical performance in PIBs.