Encapsulating lithium at the microscale: selective deposition in carbon-doped graphitic carbon nitride spheres

For stable lithium deposition without dendrites, three-dimensional (3D) porous structure has been intensively investigated. Here, we report the use of carbon-doped graphitic carbon nitride (C-doped g-C₃N₄) microspheres as a 3D host for lithium to suppress dendrite formation, which is crucial for stable lithium deposition. The C-doped g-C₃N₄ microspheres have a high surface area and porosity, allowing for efficient lithium accommodation with high accessibility. The carbon-doping of the g-C₃N₄ microspheres confers lithiophilic properties, which facilitate the regulation of Li⁺ flux and dense filling of cavities with nucleated lithium, thereby preventing volume expansion and promoting dendrite-free Li deposition. The electrochemical performance was improved with cyclic stability and high Coulombic efficiency over 260 cycles at 1.0 mA cm⁻² for 1.0 mAh cm⁻², and even over 70 cycles at 5.0 mA cm⁻² for 3.0 mAh cm⁻². The use of C-doped g-C₃N₄ microspheres as a 3D Li host shows promising results for stable lithium deposition without dendrite formation.