Fluorination of MXene by Elemental F₂ as Electrode Material for Lithium‐Ion Batteries

Abstract

What prompted you to investigate this topic/problem? Lithium-ion batteries (LIBs), due to the inherentl imitations of traditional electrode materials, have relatively low energy and power density which hinders their application for electric vehicles. In order to tackle this problem, different engineering routes are being developed to increase their performance. Therefore, we have developed ad irect-fluorination process for the formation of oxyfluorides with the aim of also improving the cost effectiveness and practicality.D irect fluorination by elemental fluorine is one of the best solutions to obtain highly pure oxyfluoride materials, whicho ur group is using for research on electrode materials. With this approach, we have demonstrated for the first time the formation of 2D-titanium oxyfluoride (TiOF 2 )v ia low temperature directfluorination.

Synthesizing High‐Capacity Oxyfluoride Conversion Anodes by Direct Fluorination of Molybdenum Dioxide (MoO2)

“…[33][34][35][36][37][38][39][40][41] Electrochemically stable oxyfluoride phases can be synthesized using either:( i) ah igh-temperature solid-state reaction [33,42] or (ii)direct fluorination of metal oxide in af luidized bed reactor (FBR) containing F 2 gas. [43,44] The latter direct fluorination method employingafluidized bed reactor (FBR) and fluorine gas was first developed by Dai'sr esearch group for mesoporous TMOs, [43] and extended for fluorinating different TMOs and different types of carbons. [44][45][46][47][48][49][50] However,a ttempts to create an oxyfluoride anionic environment around TM centers with high oxidation state are futile because of the volatile nature of such oxyfluoride compounds.…”

“…[43,44] The latter direct fluorination method employingafluidized bed reactor (FBR) and fluorine gas was first developed by Dai'sr esearch group for mesoporous TMOs, [43] and extended for fluorinating different TMOs and different types of carbons. [44][45][46][47][48][49][50] However,a ttempts to create an oxyfluoride anionic environment around TM centers with high oxidation state are futile because of the volatile nature of such oxyfluoride compounds. Herein, for the first time, we proposed ap romising strategy to solve the issue of the volatility of oxyfluoride compounds by mechanical prelithiation of TMOs with lithia (Li 2 O).…”

“…Incorporating oxyfluoride phases into MoO 2 represents an alternative approach that may improve its electrochemical performance as previously reported for similar TMO anodes (e.g., FeO, MnO, Mn 3 O 4 , TiO 2 , Nb 2 O 5 ) . Electrochemically stable oxyfluoride phases can be synthesized using either: (i) a high‐temperature solid‐state reaction or (ii) direct fluorination of metal oxide in a fluidized bed reactor (FBR) containing F 2 gas . The latter direct fluorination method employing a fluidized bed reactor (FBR) and fluorine gas was first developed by Dai's research group for mesoporous TMOs, and extended for fluorinating different TMOs and different types of carbons …”

“…Electrochemically stable oxyfluoride phases can be synthesized using either: (i) a high‐temperature solid‐state reaction or (ii) direct fluorination of metal oxide in a fluidized bed reactor (FBR) containing F 2 gas . The latter direct fluorination method employing a fluidized bed reactor (FBR) and fluorine gas was first developed by Dai's research group for mesoporous TMOs, and extended for fluorinating different TMOs and different types of carbons …”

Triple Layer Tungsten Trioxide, Graphene, and Polyaniline Composite Films for Combined Energy Storage and Electrochromic Applications

“…Graphene with the two-dimensional (2D) carbon structure can well meet the requirement owing to its unique electrical, chemical, thermal, and mechanical properties [37][38][39]. Especially, graphene has been demonstrated to stabilize the conducting polymer by forming a certain relationship thus enhancing the conductivity, energy storage ability, and cycling stability of pristine polymers [40][41][42][43]. All in all, the introduction of either WO 3 or graphene is expected to have positive effects on the electrochromic and supercapacitor performance of the pristine PANI films.In this work, we have successfully synthesized different hybrid WO 3 , graphene, and PANI films by employing combined spin coating and electro-polymerization method.…”