Self-supported GaN nanowires with cation-defects, lattice distortion, and abundant active sites for high-rate lithium-ion storage

Abstract

Although cation-deficient nanomaterials, especially one-dimensional (1D) nanowires, have demonstrated to be feasible in electrochemical energy storage as promising electrode materials, the effects of cation defects on charge transfer and electrode performance are not fully explored and understood. In this paper, the cation defects are generated in the as-prepared gallium nitride (GaN) via a cost-effective plasma process, serving as the reversible active sites to boost electrochemical performance by simultaneously promoting electrical conductivity and charge transfer. Several techniques, including XRD, TEM, XANES, cyclic voltammetry, Electrochemical impedance spectroscopy, etc., are used to characterize and understand the material morphology, structure and composition as well as the electrochemical properties. Results show that the cation-deficient GaN nanowires have abundant nanochannels, which can facilitate the rapid ionic transfer. The anode of such a material cation can deliver much higher capacities of 746.5 mAh g−1 at 0.1 A g−1 after 100 cycles and 370.2 mAh g−1 at 10 A g−1 after 1000 cycles, respectively. Density functional theory (DFT) calculations prove that benefited from the unique self-supported 1D architecture and cation defects, the local atomic arrangement and electronic structure can be tuned to significantly increase the electrical conductivity and charge transfer efficiency and subsequently boost lithium-ion storage for lithium-ion batteries. This strategy provides an accessible approach to utilize cation-defect nanomaterials for advanced electrochemical energy applications.