A Flexible Si@C Electrode with Excellent Stability Employing an MXene as a Multifunctional Binder for Lithium‐Ion Batteries

Abstract

Silicon is a promising anode material with high capacity for lithium‐ion batteries (LIBs) but suffers from poor conductivity and large volume change during charge/discharge. Herein, by using two‐dimensional conductive MXene as a multifunctional binder instead of conventional insulating polymer binders such as poly(vinylidene fluoride) or carboxymethylcellulose sodium (PVDF and CMC, respectively), a free‐standing, flexible Si@C film was fabricated by simple vacuum filtration and directly used as anode for LIBs. In the MXene‐bonded Si@C film, MXene constructed a three‐dimensional conductive framework in which Si@C nanocomposites were embedded. Its loose and porous structure provided much space to buffer the large volume expansion of Si@C nanoparticles and thus led to significantly superior cycle stability compared with conventional CMC‐ and PVDF‐bonded Si@C electrodes. Moreover, the porous structure and the metallically conductive MXene offered fast ion transport and outstanding conductivity of the MXene‐bonded Si@C film, which were favorable for its rate performance. These results promise good potential of the MXene‐bonded Si@C film electrode for LIBs.

MXene‐Based Anodes for Metal‐Ion Batteries

“…10 −14 –10 −13 cm 2 s −1 ), and a continually growing SEI which both degrades the electrode and consumes electrolyte over a short number of cycles . The use of MXenes to overcome these issues has seen a surge of interest in the last year (Table ), with titanium carbides being able to act as a multifunctional binder and reinforcement to silicon carbides, and viscous MXene inks being able to provide high Si mass loading to thick film electrodes . The first experimental example of a Si‐MXene electrode was published by Kong et al .…”

Enhanced Ionic Accessibility of Flexible MXene Electrodes Produced by Natural Sedimentation

“…Transition metal carbides, nitrides and carbonitrides, a large family of two-dimensional (2D) materials known as MXenes, have been gaining a lot of interest in a variety of applications, especially for energy storage and conversion [8][9][10]. The characteristics of MXenes, including their unique 2D morphologies, rich chemistries, ultra-high electronic conductivities, and abundant surface functional groups, make them promising candidates for electrodes of supercapacitors (SCs) and LIBs [11][12][13][14][15]. Moreover, the excellent flexibility of MXene nanosheets endows their use for flexible electrode manufacturing.…”

Electrostatically Assembling 2D Nanosheets of MXene and MOF‐Derivatives into 3D Hollow Frameworks for Enhanced Lithium Storage

“…[1] Great efforts have been made to develop new electrode materials with enhanced energy storage capability without compromising their power density and cycling stability. [2,3] Owing to their high surfaceto-volume ratio, fast charge transport, and shortened ion diffusion pathway, which are beneficial for electrochemical kinetics, 2D materials are considered as superior electrode candidates for energy storage. [4][5][6] In particular, MXene (e.g., Ti 3 C 2 T x ) as an essential member of 2D materials shows additional merits of metallic conductivity, low diffusion barrier for lithium ions, and ignorable volume change during intercalation/de-intercalation process.…”