Tunable electronic properties of free-standing Fe-doped GaN nanowires as high-capacity anode of lithium-ion batteries

Abstract

As an electrode in lithium-ion batteries (LIBs), gallium nitride (GaN) suffers from inferior conductivity and unsatisfied capacity performance. Although nanostructure designing and carbon coating strategies have been adopted to address this concern, improved Li+ storage performance remains highly desirable. In this work, Fe doping strategy was adopted in as-prepared GaN via chemical vapor deposition. Fe doping enhanced electrical conductivity and charge-transfer efficiency. Results showed that the covalent doping of Fe into GaN nanowires provided abundant nanochannels and realized efficient ionic transfer and reduced Li+ diffusion barrier. These Fe covalently doped GaN nanowire arrays exhibited capacities of up to 612.3 mAh g−1 at 0.1 A g−1 after 200 cycles and 338.2 mAh g−1 at 5.0 A g−1 after 500 cycles. Density functional theory calculations confirmed that the crystal and band structures were tuned to intensively enhance the ionic transfer efficiency and electrical conductivity and enhance the Li+ storage performance. The electron density strategy provided a significant reference for the rational construction of efficient Li+ storage electrode and beyond.

Keywords

• Fe doping
• GaN nanowires
• Anode
• Lithium-ion batteries
• Density functional theory