A Robust, Freestanding MXene‐Sulfur Conductive Paper for Long‐Lifetime Li–S Batteries

Abstract

Freestanding, robust electrodes with high capacity and long lifetime are of critical importance to the development of advanced lithium-sulfur (Li-S) batteries for next-generation electronics, whose potential applications are greatly limited by the lithium polysulfide (LiPS) shuttle effect. Solutions to this issue have mostly focused on the design of cathode hosts with a polar, sulfurphilic, conductive network, or the introduction of an extra layer to suppress LiPS shuttling, which either results in complex fabrication procedures or compromises the mechanical flexibility of the device. A robust Ti 3 C 2 T x /S conductive paper combining the excellent conductivity, mechanical strength, and unique chemisorption of LiPSs from MXene nanosheets is reported. Importantly, repeated cycling initiates the in situ formation of a thick sulfate complex layer on the MXene surface, which acts as a protective membrane, effectively suppressing the shuttling of LiPSs and improving the utilization of sulfur. Consequently, the Ti 3 C 2 T x /S paper exhibits a high capacity and an ultralow capacity decay rate of 0.014% after 1500 cycles, the lowest value reported for Li-S batteries to date. A robust prototype pouch cell and full cell of Ti 3 C 2 T x /S paper // lithium foil and prelithiated germanium are also demonstrated. The preliminary results show that Ti 3 C 2 T x /S paper holds great promise for future flexible and wearable electronics.

A Facile, High‐Yield, and Freeze‐and‐Thaw‐Assisted Approach to Fabricate MXene with Plentiful Wrinkles and Its Application in On‐Chip Micro‐Supercapacitors

“…Some small pieces were observed, and the average statistical flake size was 5.0 µm based on the TEM ( Figure a) and SEM images (Figure S8, Supporting Information). In this regard, MXene with a small flake is also widely used in most research, so boosting its yield is as important as large MXene flakes. Therefore, sonication was selected to cooperate with the FAT method.…”

Two‐Dimensional Transition Metal Carbides and Nitrides (MXenes): Synthesis, Properties, and Electrochemical Energy Storage Applications

“…The first MXene member is titanium carbide (Ti 3 C 2 T x ) prepared by immersing the Ti 3 AlC 2 powder in 50 wt.% HF solution . Right afterward, Ti 3 C 2 T x has quickly attracted much research attention in many areas focusing on synthesis routes, properties and applications . To date, Ti 3 C 2 T x is the most widely studied MXene with the most prominent performance in the electrochemical energy storage field .…”

“…Assisted by DFT calculations and XPS results, they observed the in‐situ formation of a thick sulfate complex from the interactions between the surface‐terminated hydroxyl groups and the long‐chain LIPSs. The sulfate complex layer covered the MXene surface tightly and efficiently blocked the polysulfides migration . Consequently, the S@Ti 3 C 2 T x free‐standing electrodes exhibited high capacities (1350 mAh g −1 in 50% S and 1244 mAh g −1 in 70% S electrodes), as well as ultralow capacity decay rates (<0.04 % per cycle after cycling) .…”

MXene Printing and Patterned Coating for Device Applications

“…MXenes possess high electrical conductivity and allow easy ion intercalation between layers, leading to excellent performance as electrodes for electrochemical capacitors (supercapacitors) [ 80 ] and various kinds of batteries [ 81–85 ] However, the present reports on printing MXenes for energy storage nearly all focus on supercapacitors, with few studies on the lithium‐ion battery.…”