Turning Trash into Treasure: MXene with Intrinsic LiF Solid Electrolyte Interfaces Performs Better and Better during Battery Cycling

Abstract

Commercialization of lithium ion batteries has accelerated dramatically over the last few decades. Single‐layered Ti3C2 (s‐Ti3C2) is effectively prepared by etching Ti3AlC2 via simple treatment with HCl and LiF, producing inevitably sediments always discarded after etching. This study explores the effect of LiF doping of multilayered Ti3C2 to form m‐Ti3C2/LiF consisting essentially of the sediments. Simple half‐cells assembled with m‐Ti3C2/LiF sediments suggest that LiF suppresses electrode volume expansion and surface cracking during cycling promoting Li+ intercalation/deintercalation. The data also suggest that LiF promotes formation of stable artificial solid electrolyte interfaces to prevent electrolyte and electrode degradation. The capacity of m‐Ti3C2/LiF sediments derived cells maintains 136 mAh g−1 after 1500 cycles at 300 mA g−1 while s‐Ti3C2 from supernatants physically mixed with 20 wt% LiF shows a capacity of 335 mAh g−1 (100th cycle) at 100 mA g−1 with an initial coulombic efficiency of 83%. Half‐cell anodes made of Ti3C2 etched by HF, commercial TiO2, and Sn powder mixed physically with 20 wt% LiF exhibit improved performance with cycling. These results indicate that the always discarded sediments can be directly used in LIBs and simple doping with LiF obviously improves the electrochemical performance of materials.

Synchrotron Radiation Spectroscopic Studies of Mg2+ Storage Mechanisms in High‐Performance Rechargeable Magnesium Batteries with Co‐Doped FeS2 Cathodes

“…[32] The specific surface areas (SSAs) and pore size distributions for Fe 1-x Co x S 2 (x = 0, 0.1, 0.25, 0.5) were characterized by N 2 adsorption/desorption as these properties play a crucial role in the battery performance. [33] As seen in Figure S5 and Table S6 (Supporting Information), the Brunauer-Emmett-Teller (BET) SSAs of FeS 2 , Fe 0.9 Co 0.1 S 2 , Fe 0.75 Co 0.25 S 2 and Fe 0.5 Co 0.5 S 2 are estimated to be 2, 5, 9 and 23 m 2 g -1 , respectively, as anticipated by the changes in particle sizes. Using the Barrett-Joyner-Halenda (BJH) method, FeS 2 shows pore size distribution (<20 nm) while pore size distributions (<12 nm) are seen for the Fe 0.9 Co 0.1 S 2 , Fe 0.75 Co 0.25 S 2 and Fe 0.5 Co 0.5 S 2 samples.…”

Biomimetic Porous MXene Sediment-Based Hydrogel for High-Performance and Multifunctional Electromagnetic Interference Shielding

“…The components of MS have presented in the X-ray diffraction (XRD) patterns in Figure S3. The typical diffraction peaks of Ti 3 C 2 T x MXene and Ti 3 AlC 2 MAX could be indexed in the patterns of MS, illustrating the presence of unetched MAX phase and unexfoliated m-MXene. − Scanning electron microscope (SEM) images and energy dispersive spectroscopy (EDS) mappings are also applied to record the existence of the phase components in MS (Figure c and Figure S4). As shown in the transmission electron microscope (TEM) images (Figure d,e, and Figure S5), the coexistence of MAX phase, m-MXene, and MXene layers is further verified in MS, which is consistent with the analysis in XRD and SEM.…”

Review of Design Routines of MXene Materials for Magnesium‐Ion Energy Storage Device

“…The chemical composition of MXene can be illustrated by a general formula of M n+1 X n T x , where M is the transition metal with a common element of Ti, V, Nb, Mo, Cr; A is an element dominated by IIIA or IVA such as Al, Si, Ge; X indicates C and N element or either of the two; n denotes the number of atomic layers (1)(2)(3)(4); and -T x represents the surface terminations. In Figure 2a, the possible constituent atoms of a ternary ceramic material MAX phase are shown, in which it is typically fabricated through ball milling and high temperature sintering.…”