Stable Cycle Performance of a Phosphorus Negative Electrode in Lithium-Ion Batteries Derived from Ionic Liquid Electrolytes

Abstract

Although high-capacity negative electrode materials are seen as a propitious strategy for improving lithium-ion battery (LIB) performance, their advancement is curbed by issues such as pulverization during charge-discharge and the formation of unstable solid electrolyte interphase (SEI). In particular, electrolytes play a vital role to determine the properties of SEI layer. Thus, in this study, we investigate the performance of a red phosphorus/acetylene black composite (P/AB) prepared by high energy ball-milling as a negative electrode material for LIBs using organic and ionic liquid (IL) electrolytes. Galvanostatic tests performed on half cells demonstrate high discharge capacities in the 1386-1700 mAh (g-P/AB) −1 range along with high Coulombic efficiencies of 85.3-88.2 % in the 1st cycle, irrespective of the electrolyte used. Upon cycling, the Li[FSA]-[C2C1im][FSA] (FSA − = bis(fluorosulfonyl)amide and C2C1im + = 1-ethyl-3methylimidazolium) IL electrolyte (2:8 in mol) demonstrates a high capacity retention of 78.8% after 350 cycles, whereas significant capacity fading is observed in the Li[PF6] and Li [FSA] organic electrolytes. Electrochemical impedance spectroscopy conducted with cycling revealed lower interfacial resistance in the IL electrolyte than in the organic electrolytes. Scanning electron microscopy and X-ray photoelectron spectroscopy after cycling in the different electrolytes evinced that the IL electrolyte facilitates the formation of a robust SEI layer comprising multiple layers of sulfur species resulting from FSA − decomposition. A P/AB|LiFePO4 full-cell using the IL electrolyte showed superior capacity retention than organic electrolytes and a high energy density under ambient conditions. This work not only illuminates the improved performance of a phosphorous-based negative electrode alongside ionic liquid electrolytes but also displays a viable strategy for the development of high performance LIBs especially for large-scale applications.

In Situ Orthorhombic to Amorphous Phase Transition of Nb2O5 and Its Temperature Effect on Pseudocapacitive Behavior

“…It is worth noting that the amount of S- and N-based components is considered to be one of the key differentiators between SEI layers formed by organic electrolytes (e.g., Li­[PF 6 ]-EC/DMC) and IL electrolytes (e.g., Li­[FSA]-[C 2 C 1 im]­[FSA]). In fact, previous studies on NIBs and LIBs utilizing [FSA] − -based electrolytes have identified the abundance of sulfur-based components in the SEI layer as the main factor behind their improved electrochemical performance in ILs …”

“…In fact, previous studies on NIBs and LIBs utilizing [FSA] − -based electrolytes have identified the abundance of sulfur-based components in the SEI layer as the main factor behind their improved electrochemical performance in ILs. 70…”

Review on Action Mechanism and Characterization of Natural/Artificial Solid Electrolyte Interphase of Lithium Battery: Latest Progress and Future Directions

“…Not only that, the size of the SEI itself will also affect its own stability. For example, when Bian et al studied tea polyphenols (TP) as a new reactive electrolyte additive applied to lithium-ion batteries, − they found that the additive TP can remove ethylene carbonate and form a stable polymer. It is concluded that the thickness of the SEI film will affect its own stability, and the additive TP can react with unstable free radicals to form a polymer, which greatly improves the stability of the SEI film.…”

Review on the Energy Transformation Application of Black Phosphorus and Its Composites

“…Strong covalent bonds form within single layers, in between which it is van der Waals force [37][38][39][40][41][42][43]. With this unique lattice structure, black phosphorus shows better stability than its allotropes (white and red phosphorus), and it also has high carrier mobility, anisotropic in-plane properties and specific capacity [21,[44][45][46], which makes it ideal as negative electrode material for lithium and sodium batteries [30,[47][48][49][50][51][52][53], as well as photocatalysts. With construction [54][55][56][57][58], doping [59][60][61][62][63][64], or heterojunctions [65][66][67][68][69][70][71], the stability, charge transport, and catalytic performance of black phosphorus can be further improved.…”