Three-Dimensional Porous Diboron Dinitride as a High-Performance Anode Material for Sodium/Potassium-Ion Batteries: A First Principles Study

2D boron nitride shows great promise in the photoelectric device, deep UV emitter and field effect transistor with good thermal stability, high mechanical robustness and chemical inertness; nonetheless, its inherently low electrical conductivity and small pore size have severely hindered the electrochemical kinetics and lead to a poor rate capability. Herein, we design a novel porous 3D-B2N2 structure by assembling the orthorhombic B2N2 monolayer into t-C24 lattice and assesse its feasibility as the anode material of sodium(SIBs)/potassium(PIBs) ion batteries. The ab initio molecular dynamics (AIMD) simulation, Born-Huang criteria, phonon spectrum and cohesive energy calculations confirms that the resulting 3D-B2N2 possesses excellent mechanical, thermal and dynamical stability. Different from the pristine h-B2N2, an improved electrical conductivity is observed for 3D-B2N2 with a small band gap of 0.66 eV. Moreover, the low mass density, unique porous structure and strong adsorption energy make the 3D-B2N2 an outstanding electrode material for SIBs/PIBs with high storage capacities of 599.90 (479.92) mA h/g, low averaged open circuit voltages of 0.13 (0.27) V, low diffusion barriers of 0.04 (0.008) eV, and small volume expansions of 0.96 % (2.63 %). All the encouraging findings reveal that the 3D-B2N2 anode deserves further experimental investigation for SIBs/PIBs. Motivated by the great success of 3D carbon materials and MXenes, design a novel porous 3D-B2N2 structure was designed by assembling the orthorhombic B2N2 monolayer into t-C24 lattice. Its potential use as an anode material of sodium(SIBs)/potassium(PIBs) ion batteries was assessed using first principles calculations. The resulting 3D-B2N2 has excellent mechanical, dynamical and thermal stability with improved electrical conductivity. In addition, due to the low mass density, unique porous structure and strong adsorption energy, the 3D-B2N2 anode achieves high storage capacities of 599.90 (479.92) mA h/g, low averaged open circuit voltages of 0.13 (0.27) V, low diffusion barriers of 0.04 (0.008) eV, and small volume expansions of 0.96 % (2.63 %) for SIBs/PIBs.image