Two-dimensional Be 2 P 4 as a promising thermoelectric material and anode for Na/K-ion batteries

Incredibly effective and flexible energy conversion and storage systems hold great promise for portable self-powered electronic devices. Owing to their large surface area, exceptional atomic structures, superior electrical conductivity and good mechanical flexibility, two-dimensional (2D) materials are recognized as an attractive option for energy conversion and storage application. In this work, we examined the stability, electronic, thermoelectric and electrochemical aspects of a novel 2D Be P monolayer by adopting density functional theory (DFT). The Be P monolayer exhibits a direct semiconductor gap of 0.9 eV (HSE06), large Young's modulus (∼198 GPa), high carrier mobility (∼10 cm V s ) and a low excitonic binding energy of 0.11 eV. Our calculated findings suggest that Be P shows a lattice thermal conductivity of 1.02 W m K at 700 K, resulting in moderate thermoelectric performance ( ∼ 0.7), encouraging its use in thermoelectric materials. In addition, a higher adsorption energy of -2.28 eV (-2.52 eV) and less diffusion barrier of 0.22 eV (0.17 eV) for Na(K)-ion batteries promote fast ion transport in the Be P monolayer. This material also shows a high specific capacity and superior energy density of 8460 W h kg (8883 W h kg ) for Na(K)-ion batteries. Thus, our results offer insightful information for investigating potential thermoelectric and flexible anode materials based on the Be P monolayer.