Diethylenetriamine-directed selective formation of carbon-confined ultrafine MoO2 nanocrystals via one-pot spray pyrolysis for highly reversible and long-life Li-ion anodes

초록

The growing demand for high-power lithium-ion batteries (LIBs) necessitates anode materials that simultaneously deliver rapid charge-discharge kinetics and long-term durability. Molybdenum dioxide (MoO2) is an attractive candidate due to its metallic conductivity (similar to 10(3) S cm(-1)) and high theoretical capacity (838 mA h g(-1)); however, its practical application is limited by facile oxidation to MoO3 during synthesis and sluggish Li-ion diffusion in dense bulk crystallites. Herein, a diethylenetriamine (DETA)-directed one-pot spray pyrolysis strategy is developed to selectively form ultrafine MoO2 nanocrystals under an air atmosphere. During aerosol decomposition, strong Mo-N coordination induced by DETA suppresses over-oxidation and directs phase-selective crystallization toward MoO2, while polyvinylpyrrolidone serves as a carbonizable scaffold to generate a conformal N-doped carbon matrix that confines the nanocrystals and enhances structural integrity. As a result, the carbon-confined MoO2 nanocomposite exhibits accelerated charge-transfer kinetics, enhanced Li-ion diffusion, and suppressed impedance growth upon prolonged cycling. The optimized anode delivers a high reversible capacity of 541 mA h g(-1) after 400 cycles at 1.0 A g(-1) and maintains 415 mA h g(-1) at 2.0 A g(-1). Furthermore, a comparative techno-economic analysis demonstrates that the DETA-assisted route significantly reduces processing costs by eliminating post-reduction steps required in conventional spray-pyrolyzed MoO2 synthesis. This work provides mechanistic insight into coordination-driven MoO2 phase selectivity and establishes a scalable, economically viable pathway toward high-rate LIB anodes.

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