Nano-sized MoO2 spheres interspersed three-dimensional porous carbon composite as advanced anode for reversible sodium/potassium ion storage

Recently, MoO2 has been widely studied as an anode material owing to its high theoretical capacity and stability. In this study, nano-sized MoO2 is successfully fabricated on three-dimensional porous carbon (3DPC) using a simple hydrothermal method followed by calcination. The composite exhibits higher surface area (171.6 m(2)g(-1)) than that of bulk MoO2 (81.4 m(2) g(-1)). For the first time, the novel MoO2/3DPC composite is tested in both sodium and potassium ion batteries. The MoO2/3DPC composite exhibits improved electrochemical performance than that of bulk MoO2 powder. In Na+ half cells, the specific charge capacity in the first cycle of the MoO2/3DPC composite at 0.1 A g(-1) is similar to 463 mAh g(-1) and a reversible capacity of similar to 367 mAh g(-1) can be maintained after 200 cycles. In K+ half cells, the initial charge capacity is similar to 350 mAh g(-1) at 0.05 A g(-1). In addition, a reversible charge capacity of as high as 213 mAh g(-1) can be maintained after 200 cycles. The synergistic effect of 3DPC and nano-sized MoO(2 )improves the electrochemical performance. The unique 3D structure of porous carbon can increase the electrical conductivity and alleviate the absolute stress/strain. Results demonstrate that the MoO2/3DPC composite is one of the promising candidates for Na+/K+ storage. (C) 2019 Elsevier Ltd. All rights reserved.