Elastic Sandwich‐Type rGO–VS₂/S Composites with High Tap Density: Structural and Chemical Cooperativity Enabling Lithium–Sulfur Batteries with High Energy Density

Abstract

Driven by increasing demand for high‐energy‐density batteries for consumer electronics and electric vehicles, substantial progress is achieved in the development of long‐life lithium–sulfur (Li–S) batteries. Less attention is given to Li–S batteries with high volume energy density, which is crucial for applications in compact space. Here, a series of elastic sandwich‐structured cathode materials consisting of alternating VS2‐attached reduced graphene oxide (rGO) sheets and active sulfur layers are reported. Due to the high polarity and conductivity of VS2, a small amount of VS2 can suppress the shuttle effect of polysulfides and improve the redox kinetics of sulfur species in the whole sulfur layer. Sandwich‐structured rGO–VS2/S composites exhibit significantly improved electrochemical performance, with high discharge capacities, low polarization, and excellent cycling stability compared with their bare rGO/S counterparts. Impressively, the tap density of rGO–VS2/S with 89 wt% sulfur loading is 1.84 g cm−3, which is almost three times higher than that of rGO/S with the same sulfur content (0.63 g cm−3), and the volumetric specific capacity of the whole cell is as high as 1182.1 mA h cm−3, comparable with the state‐of‐the‐art reported for energy storage devices, demonstrating the potential for application of these composites in long‐life and high‐energy‐density Li–S batteries.

In Situ Assembly of 2D Conductive Vanadium Disulfide with Graphene as a High‐Sulfur‐Loading Host for Lithium–Sulfur Batteries

“…As shown in Figure 6c, G-VS 2 with different sulfur loadings has been examined by cycling at 1 C. After 150 cycles, a reversible capacity of 923, 559, and 520 mAh g −1 is retained with sulfur loadings of 1.0, 2.0, and 3.5 mg cm −2 , corresponding to capacity retentions of 72.7%, 71.1%, and 74.2%, respectively. Impressively, a systematic study with respect to rGO-VS 2 as sulfur hosts has recently been demonstrated realizing high energy density and tap density, [32] it is noted that our work is otherwise differentiated by certain key aspects from synthetic procedure of products through theoretical considerations, to electrochemical performances at high rates and high sulfur loadings. Moreover, deep cycling of sulfur-loaded electrodes (1.3 and 2.0 mg cm −2 ) at 2 C rate also discloses capacity stabilities over 200 cycles ( Figure S16, Supporting Information).…”

“…The metallic feature has already enabled VS 2 , especially its 2D form, to become a versatile platform for multifunctional applications such as supercapacitor, [26] nanoelectronics, [27][28][29] and hydrogen evolution. [19,32,33] It is worth noting that most of the fabrication strategies involved in these pioneer work for VS 2 -based sulfur cathodes normally dealt with simple mechanical/physical mixing of VS 2 nanostructures with carbonaceous materials, which could result in an uneven distribution of VS 2 and an ineffective contact in between. [19,32,33] It is worth noting that most of the fabrication strategies involved in these pioneer work for VS 2 -based sulfur cathodes normally dealt with simple mechanical/physical mixing of VS 2 nanostructures with carbonaceous materials, which could result in an uneven distribution of VS 2 and an ineffective contact in between.…”

“…The electrode could still deliver a reversible capacity of 800 mAh g −1 (4.0 mAh cm −2 ) after 50 cycles, indicating outstanding cycling stability even with such a high sulfur loading. [32,[48][49][50][51] The excellent cycling performance of the high loading electrodes marks the integrated advances of the high conductivity, accelerated polysulfide redox kinetics, as well as effective polysulfide chemical confinement of the G-VS 2 sulfur hosts. As shown in Figure 6c, G-VS 2 with different sulfur loadings has been examined by cycling at 1 C. After 150 cycles, a reversible capacity of 923, 559, and 520 mAh g −1 is retained with sulfur loadings of 1.0, 2.0, and 3.5 mg cm −2 , corresponding to capacity retentions of 72.7%, 71.1%, and 74.2%, respectively.…”

Novel 2D Sb2S3 Nanosheet/CNT Coupling Layer for Exceptional Polysulfide Recycling Performance

“…[29] ii) They should have suitable Li diffusion characteristics with highly efficient polysulfide attraction and adsorption. [35][36][37][38][39] Disappointingly, however, only very few 2D materials, including phosphorene [40] and defective borophene, [41] have so far been able to simultaneously satisfy the abovementioned two criteria while these coupling materials have yet to be fully explored. [35][36][37][38][39] Disappointingly, however, only very few 2D materials, including phosphorene [40] and defective borophene, [41] have so far been able to simultaneously satisfy the abovementioned two criteria while these coupling materials have yet to be fully explored.…”

Nanoparticle Assembled Mesoporous MoO2 Microrods Derived from Metal Organic Framework and Wrapped with Graphene as the Sulfur Host for Long‐Life Lithium–Sulfur Batteries

“…[2] Several approaches, including physical confinement, [3] chemical confinement, [4] integrating sulfur into conductive matrix, [5] interlayers, [6] modified separators, [7] and functional binders, [8] have been developed. In light of this, a small dosage of polar materials such as metal oxides, [11,12] sulfides, [13,14] nitrides, [15] and carbides [16] into sulfur cathodes are extensively investigated.Several polar metal oxides based sulfur hosts were investigated and found to be promising due to strong adsorption of polysulfides on polar surfaces. [9] Considering of the weak interaction between routine nonpolar carbon materials and polar polysulfides, heteroatom doping has been adopted to bind polar sulfur based on guest-host interactions.…”