Ultrathin 2D TiS₂ Nanosheets for High Capacity and Long‐Life Sodium Ion Batteries

Abstract

greenhouse emissions and environmental pollution can be effectively reduced. In this regard, sodium ion batteries (SIBs) possess the merits of low cost and abundance. [1,2] The sluggish kinetics of sodium ion diffusion caused by the large sodium ionic radius, however, results in poor cycling stability, and low rate performance. Fully understanding the structural evolution during electrochemical reactions and achieving the corresponding improvements in the crystal structure and morphology design are urgently required to promote the development of SIBs. [3] Recent research progress has involved a considerable emphasis on constructing nanostructures with high surface area to take advantages of impressive nanochemistry, including ultrathin layered materials. The discovery of graphene has a spillover effect, leading to unprecedented research on single-layer and few-layer 2D materials. [4] The evergrowing family of 2D crystals offers versatile benefits owing to their unique physical and chemical properties in terms of diversity of applications, such as rechargeable batteries, catalysts, membranes, conductive or inert coatings, etc. [5][6][7] 2D materials in particular have been treated as a robust host for sodium storage. [8] By downsizing from the bulk to a few atomic layers, both physical and chemical properties have shown outstanding improvements. [9][10][11] Different methods, including chemical vapor deposition (CVD) growth, [12] chemical-assisted exfoliation, [13][14][15] and direct exfoliation, [16] have shown their application in preparation of few-layer 2D materials. Among them, shear exfoliation is driven by the high shear rate generated by a highspeed rotator, [17] and can even be achieved by using a kitchen blender. [18] This facile and low-cost method is easy to use for scaling up in industrial production line.Transition metal dichalcogenides have been widely investigated in battery systems, due to their tunable interlayer space, fast ion transportation, and robust kinetics. [19] Among them, TiS 2 is a promising electrode material due to its low cost, facile synthesis, and high specific discharge capacity of 479 mAh g −1 (calculated based on the two-electron reaction, 1C = 479 mA g −1 ). [20] Recently, TiS 2 has been reported as good electrode materials for lithium ion batteries, [21] potassium ion batteries, [22,23] magnesium ion batteries, [24,25] and calcium ion batteries. [25] The ever-growing interests for TiS 2 in energy storage and conversion system also promotes the research in SIBs. Ryu et al. used TiS 2 powder purchased from Sigma-Aldrich as the electrode material for SIBs. [26] The discharge Sodium ion batteries are now attracting great attention, mainly because of the abundance of sodium resources and their cheap raw materials. 2D materials possess a unique structure for sodium storage. Among them, transition metal chalcogenides exhibit significant potential for rechargeable battery devices due to their tunable composition, remarkable structural stability, fast ion transport, and robust kinetic...

Manipulating 2D Few‐Layer Metal Sulfides as Anode Towards Enhanced Sodium‐Ion Batteries

“…The few-layer MoS 2 nanosheets were in situ grown on the surface of rGO as well as HCS by hydrothermal method. [38] As shown in Figure 3c, the TEM image clearly identified the 3D interconnected [94] structure, where the MoS 2 nanosheets well cross-linked with hollow nanospheres and the rGO surface. Also, the HRTEM images revealed that the number of layers of MoS 2 can be tuned from single-layer to few-layer (2-5 layers) with an enlarged interlayer distance of 0.69 nm (vs. 0.62 nm for pristine MoS 2 ) (Figure 3d).…”

“…MSs (MS x , M=Fe, Co, Ni, Cu, Zn, Sb, Bi, Ti) have a low price raw‐material source and high theoretical capacity, which make them very competitive compared to other anode materials . Also, the layered metal sulfides (MS x , M=Mo, Sn, W, V), have a similar layered structure of graphite, showing an excellent cycling performance .…”

2 D Materials for Electrochemical Energy Storage: Design, Preparation, and Application

“…[72] Hu et al synthesized ultrathin TiS 2 nanosheets by as hear-mixingm ethod, which exhibited outstanding cycling performance in SIBs with 386 mAh g À1 after 200 cycles at 0.2 Ag À1 . [73] Sun et al prepared MoS 2 /graphene nanosheets by ball milling and exfoliation of commercialb ulky MoS 2 and graphite. [74] As anode materials for SIBs, the as-prepared MoS 2 / graphene nanosheets exhibited remarkably high rate capability with capacities of 284 mAh g À1 at 20 Ag À1 and 201 mAh g À1 at 50 Ag À1 .C ompared with TMDs, MXenes usually have much higher conductivities and larger tunable interlayer spacings, which maket hem promising host materials for Na.…”

Hollow Structure VS2@Reduced Graphene Oxide (RGO) Architecture for Enhanced Sodium‐Ion Battery Performance

“…[9,10] Compared to Li-ion batteries, sodium-ion batteries (SIBs) have aroused growing research interests in large-scale energy storage systems because of low prices and rich natural abundance of sodium. [11,12] In addition, SIBs have similar chemistry intercalation mechanism with LIBs, which are based on the reversible Na ions intercalation/deintercalation in the positive and negative electrodes during discharge and charge process. [13,14] Generally, favorable anode materials with long life, great cycling stability and high rate performance, are the most important factors for the commercial development of SIBs.…”