In-situ synthesis of MoO2/MoS2 nanoparticles embedded in nitrogen-doped carbon foam as an anode for ultra long-life lithium-ion battery
Yalda Tarpoudi Baheri, Mohammad Ali Hedayati, Mahdi Maleki, Hossein Karimian, Ahmad Shokrieh, M.M. Shokrieh, Abolhassan Imani, Yao Tong
Abstract
Molybdenum-based materials have emerged as highly encouraging lithium-ion batteries (LIBs) anodes due to their substantial specific capacity, fast electrochemical dynamics, and superior electronic conductivity. In this study, a confined calcination method is introduced for the synthesis of molybdenum dioxide/molybdenum disulfide (MoO 2 /MoS 2 ) nanoparticles within a porous nitrogen-doped carbon matrix (C/MoO 2 /MoS 2 ). For such a goal, a novel stable poly(HIPE) constructed from polyacrylonitrile (PAN), polydivinylbenzene (PDVB), ammonium heptamolybdate (AHM), and ammonium persulfate (APS) was introduced as a reaction platform. In-situ calcination of AHM during pyrolysis led to the formation of ultrafine MoO 2 nanoparticles in the nitrogen-doped carbon framework derived from PAN and PDVB carbonization . Gaseous sulfur from the thermal decomposition of well-distributed APS in the proposed poly(HIPE) formed a thin layer of MoS 2 on the MoO 2 nanoparticles to form a MoO 2 /MoS 2 hybrid in the carbon foam. A key advantage of this synthesis method is the formation of ultrafine MoO 2 /MoS 2 nanoparticles within the carbon matrix. This benefit arises from the confinement of the molybdenum precursor within the initial polymer, which subsequently transforms into a carbon support. In other words, as the polymer decomposes to establish the carbon framework, MoO 2 /MoS 2 nanoparticles nucleate and grow within these restricted spaces. The confined MoO 2 /MoS 2 nanoparticles in the conductive porous network of carbon resulted in a heterostructure with abundant active electrochemical nanospots and rapid ion/electron transportation in the lithium charge/discharge process of LIBs. As an anode material for LIBs, the C/MoO 2 /MoS 2 composite exhibits a reversible capacity of 541 mAh g −1 after 100 cycles at a current density of 0.2C and maintains a reversible capacity of 140 mAh g −1 after 3000 cycles at 10C. This study highlights the potential of the C/MoO 2 /MoS 2 composite as an electrode material for long-life lithium-ion batteries.