Controlling Electrochemical Lithiation/Delithiation Reaction Paths for Long-cycle Life Nanochain-structured FeS2 Electrodes

Abstract

Pyrite (FeS2) stands out from other metal sulfides due to its abundance, low toxicity and high specific energy density. However, the low utilization and short cycle life of FeS2 caused by irreversible side reactions and dramatic structural changes during charge/discharge process seriously hinders its practical application. In this work, we designed FeS2 nanochains to address these issues because this unique structure not only shortens the ion/electron diffusion distance, increases the electrode/electrolyte contact area, but also accommodates the strain associated with Li ion intercalation and deintercalation reactions. Compared with nanoparticles, the FeS2 nanochains synthesized by magnetic-field-assisted aerosol pyrolysis could cycle up to 800 cycles at 0.5 C, remained a discharge capacity of 342.4 mA h g −1 in the voltage range of 1.0-2.6 V and achieved a remarkable capacity fading rate of 0.02% per cycle, which is among the best values demonstrated so far for Li/FeS2 cells. In-situ Raman experiments revealed that the irreversible side reactions could be suppressed through controlling the voltage window, which can be benefit for further improving the performance of Li/FeS2 cells.

1D Colloidal chains: recent progress from formation to emergent properties and applications

“…88,313,314,747,750,751 Similar to 1D chains in catalysts, charge transfer has also to be taken into consideration when using 1D colloidal chains as energy materials because electron/ion transport affects the high-rate performance of lithium/sodium-ion batteries. 752 Therefore, electrode materials including LiCoO 2 , 753 Fe 3 O 4 , 297 FeS 2 754 and Au-Pt 755 have been assembled into 1D colloidal chains, or integrated with carbon nanotubes 746,756,757 and carbon nanofibers. [758][759][760] These 1D structures further form 3D interconnected, electrically conductive networks to facilitate charge transfer (Fig.…”

“…28c). 305,364,747,751,754,761 A widespread challenge existing in lithium/sodium-ion batteries is volumetric expansion of electrode materials in the course of lithium/sodium insertion/extraction. Loading nanoscale active materials into/onto 1D colloidal chains to downsize the dimensions of active components, 743,759,762 and coating them with another material (usually a layer of carbon film) to suppress the expansion 748,763 are two main strategies coupled with 1D colloidal chains to address this challenge (Fig.…”

Review of Recent Development of In Situ/Operando Characterization Techniques for Lithium Battery Research

“…[312] FeS2 in situ Irreversible side reactions could be suppressed through controlling the voltage window. [313] Electrolyte P(EO)20LiTFSI polymer electrolyte in situ (confocal) Salt concentration gradients in electrolyte, diffusion coefficient and ionic transport number were determined. [279] Interface characterization glassy carbon in situ Ramm/FTIR Effect of VC and ES on SEI formation were studied by Raman/FTIR for interfacial and structure characterization.…”

Determination of Cyclability of Li/FeS2 Batteries Based on Measurement of Coulombic Efficiency

“…The Li 2 Fe 2 S 2 is formed in one voltage plateau during the initial discharge, and the reaction involves a reduction in metallic Fe and Li 2 S at 1.4 V [9]. After discharge, a consecutive charge shows that FeS and Li 2 S n are formed, and these compounds are combined into a complex of polysulfides with partial oxidation to FeS 2 [9,10] that represents a decrease in capacity from the 1st to the 2nd discharge and subsequent cycles [6,11,12] particularly because of the dissolution of intermediates such as lithium polysulfide (Li 2 S n , 4 < n < 8) in the liquid electrolyte [11,[13][14][15][16]].…”