Double‐Shelled Hollow SiO₂@N‐C Nanofiber Boosts the Lithium Storage Performance of [PMo₁₂O₄₀]³⁻

Abstract

Polyoxometalates (POMs)-based materials, with high theoretical capacities and abundant reversible multielectron redox properties, are considered as promising candidates in lithium-ion storage. However, the poor electronic conductivity, low specific surface area and high solubility in the electrolyte limited their practical applications. Herein, a double-shelled hollow PMo 12 À SiO 2 @NÀ C nanofiber (PMo 12 À SiO 2 @NÀ C, where PMo 12 is [PMo 12 O 40 ] 3À , NÀ C is nitrogen-doped carbon) was fabricated for the first time by combining coaxial electrospinning technique, thermal treatment and electrostatic adsorption. As an anode material for LIBs, the PMo 12 À SiO 2 @NÀ C delivered an excellent specific capacity of 1641 mA h g À 1 after 1000 cycles under 2 A g À 1 . The excellent electrochemical performance benefited from the unique double-shelled hollow structure of the material, in which the outermost NÀ C shell cannot only hinder the agglomeration of PMo 12 , but also improve its electronic conductivity. The SiO 2 inner shell can efficiently avoid the loss of active components. The hollow structure can buffer the volume expansion and accelerate Li + diffusion during lithiation/delithiation process. Moreover, PMo 12 can greatly reduce charge-resistance and facilitate electron transfer of the entire composites, as evidenced by the EIS kinetics study and lithium-ion diffusion analysis. This work paves the way for the fabrication of novel POM-based LIBs anode materials with excellent lithium storage performance.

Recent Advances in Confining Polyoxometalates and the Applications

“…PMo 12 was loaded on SiO 2 spheres, and then the SiO 2 -PMo 12 composite was confined with rGO to generate the SiO 2 -PMo 12 @rGO. [105,106] The introduction of SiO 2 and the confinement of rGO made POMs located in the double-shell hollow structure, preventing its loss and agglomeration and improving the conductivity of the composite material. In addition, this unique double-shell mesoporous structure provided buffer space for volume change during charge and discharge.…”

Laser-Triggered High Graphitization of Mo2C@C: High Rate Performance and Excellent Cycling Stability as Anode of Lithium Ion Batteries

“…With the rapid progress of modern science and technology, higher requirements are put forward for the performance of batteries. , The lithium-ion battery (LIB) graphite anode materials are currently challenging to meet the demand for high-rate performance batteries owing to their limited theoretical capacity (372 mA h g –1 ). , Fortunately, advanced anode materials according to alloying or conversion reaction mechanisms have shown significantly greater theoretical capacities (which can exceed 1000 mA h g –1 ), showing the potential to become alternative anode materials. – …”