Although a theoretical specific capacity of lithium/sulfur redox couple battery is 1672
mAh/g, lithium/sulfur battery has the serious problems of low utilization of active material and poor ...rechargeability, due to the loss of active material in the form of soluble polysulfides (Li
2S
n
,
n
>
2). In this study, carbon nano-fiber having average fiber diameter of 150
nm was added into the sulfur electrode in order to improve cycling property. The effect of binder on cycling property was also investigated. All cycle tests were conducted in the range of 1.5–3.2
V at room temperature. Sulfur electrodes with carbon nano-fiber using PEO and PVdF as binders, respectively, showed better cycle property than sulfur electrode without carbon nano-fiber.
Silicon-sulfur (Si-S) full cells show significant potential in energy storage due to their high theoretical energy density compared to commercial lithium-ion batteries. Nevertheless, a majority of ...electrolytes reported for Si-S full cells still cannot meet the requirements of stable long-duration cycling. Herein, we report a high-areal-capacity Si-S full cell consisted with prelithiated SiO, thick Li2S-Se0.05S0.95@pPAN electrode and a trifluorobenzene (F3B) modified and diluted high-concentration electrolytes. This novel electrolyte can effectively mitigate the volume expansion of the prelithiated SiO anode and enhance the utilization of active S in the cathode, showing excellent compatibility with electrodes. The assembled Si-S full cell using modified electrolyte displays remarkable cyclability over 100 cycles at 0.1C, exhibiting higher capacity retention (54.0% vs. 17.5%) than the pristine electrolyte without F3B. More importantly, a full cell with a thick sulfur cathode (16 mg/cm2) exhibits a superior initial areal capacity of 8.34 mAh/cm2 and high-capacity retention of 52% after 80 cycles, even at a lean electrolyte condition (2 μL/mg). This work provides guidance for the achievement of high-performance Si-S full cells under lean electrolytes.
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•An integrated approach is developed to enable high-performance silicon-sulfur full cells.•FB-DHCE-F3B shows high ionic conductivity and good compatibility with high-loading electrodes.•The high-loading Si-S full cell (16 mg cm−2) delivers a high areal capacity of 8.34 mAh/cm2 at lean electrolyte (E/S = 2).
Sulfur, as a cathode material for lithium-sulfur batteries, has a highly theoretical capacity of 1672 mAh g
−1
. However, the diffusion and dissolution of intermediate polysulfides and volume changes ...result in a rapid decay of capacity. In this work, an acidifying acetylene black/carbon nanotubes@sulfur (H-AB/CNTs@S) hybrid electrode material with a 3D interlinked network structure has been synthesized by grafting polyethylene glycol (PEG) and then depositing elemental sulfur on the commercial H-AB/CNTs hybrid surface. The H-AB/CNTs@S hybrids are characterized by Fourier transform infrared (FTIR), scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), and electrochemical methods. The H-AB/CNTs hybrid substrate provides electrons and Li ion transfer pathway for the sulfur electrode. The PEG chains with abundant hydrophilic functional groups can help alleviate the diffusion of hydrophilic polysulfides. As a result, the H-AB/CNTs@S hybrid electrode with PEG delivers a high initial discharge capacity of 1380 mAh g
−1
at a current density of 0.1 C and remains at 923 mAh g
−1
after 100 cycles.
Lithium||sulfur (Li||S) batteries are considered as one of the promising next‐generation batteries due to the high theoretical capacity and low cost of S cathodes, as well as the low redox potential ...of Li metal anodes (−3.04 V vs. standard hydrogen electrode). However, the S reduction reaction from S to Li2S leads to limited discharge voltage and capacity, largely hindering the energy density of Li||S batteries. Herein, high‐energy Li||S hybrid batteries were designed via an electrolyte decoupling strategy. In cathodes, S electrodes undergo the solid‐solid conversion reaction from S to Cu2S with four‐electron transfer in a Cu2+‐based aqueous electrolyte. Such an energy storage mechanism contributes to enhanced electrochemical performance of S electrodes, including high discharge potential and capacity, superior rate performance and stable cycling behavior. As a result, the assembled Li||S hybrid batteries exhibit a high discharge voltage of 3.4 V and satisfactory capacity of 2.3 Ah g−1, contributing to incredible energy density. This work provides an opportunity for the construction of high‐energy Li||S batteries.
High‐energy Li||S hybrid batteries were designed via matching S cathodes in aqueous Cu2+ ion‐based electrolyte and Li anodes in organic electrolyte. The Li||S hybrid batteries deliver a high discharge voltage and satisfactory capacity, contributing to incredible energy density.
•PNMP can be modified on the surface of the S/C electrode by electropolymerization.•The PNMP-modified S/C electrode exhibits a much improved cycling stability.•The possible mechanism of surface ...modification is illustrated and discussed.
Sulfur has the highest redox capacity in all the solid electrode materials but its application for Li-S batteries is restricted by its poor cycleability due to the dissolution of its polysulfide intermediates produced during charge and discharge reactions. To solve this problem, we proposed a new strategy to suppress the dissolution of the polysulfide intermediates and the agglomeration of the discharge products through surface-modification of the sulfur electrode by in-situ electropolymerized poly(N-methylpyrrole) (PNMP). The PNMP-modified sulfur electrode exhibits stable surface morphology during charge and discharge, effectively depressing the structural collapse of the sulfur electrode. The charge-discharge measurements reveal that the PNMP-modified S/C electrode can deliver the same high reversible capacity as the bare electrode but demonstrate a much improved cycling stability with excellent capacity retention of 78.1% over 200 cycles with respect to the discharge capacity in the third cycle, considerably higher than that of the bare electrode (59.8%). In addition, this surface modification method is simple and affordable, providing a feasible way for improving the long-term cycleability of Li-S batteries.
Lithium/sulfur (Li/S) cells that offer an ultrahigh theoretical specific energy of 2600 Wh/kg are considered one of the most promising next-generation rechargeable battery systems for the ...electrification of transportation. However, the commercialization of Li/S cells remains challenging, despite the recent advancements in materials development for sulfur electrodes and electrolytes, due to several critical issues such as the insufficient obtainable specific energy and relatively poor cyclability. This review aims to introduce electrode manufacturing and modeling methodologies and the current issues to be overcome. The obtainable specific energy values of Li/S pouch cells are calculated with respect to various parameters (e.g., sulfur mass loading, sulfur content, sulfur utilization, electrolyte-volume-to-sulfur-weight ratio, and electrode porosity) to demonstrate the design requirements for achieving a high specific energy of >300 Wh/kg. Finally, the prospects for rational modeling and manufacturing strategies are discussed, to establish a new design standard for Li/S batteries.
Polyelectrolytes are promising binders for sulfur cathodes of Li/S batteries, with an ability to control the diffusion of polysulfides into the electrolyte, but their impact on the microstructural ...evolution of the electrode with cycling is presently unknown. In this study, coupled in situ synchrotron X-ray diffraction and tomography analyses are performed during the 1st and 11th cycles of a sulfur-based electrode made with poly(diallyldimethylammonium) bis(trifluoromethane sulfonyl)imide as a polyelectrolyte binder. Sulfur deposited at the end of the 1st charge is mainly β-S8, but some α-S8 is also deposited during the 1st charge on the unreacted α-S8 particles. No α-S8 is detected at the 11th cycle, suggesting that the remaining α-S8 reacts progressively with cycling. The carbon-binder domain is not discernible due to spatial and contrast resolution limitations, and thus, its evolution with cycling and its specific role on the sulfur dissolution and deposition processes cannot be clearly established. However, the fact that there is no collapsing of the electrode in the sulfur-depleted zones (in contrast to what was observed in the literature with a conventional binder such as poly(vinylidene difluoride) (PVdF)) suggests that the present polyelectrolyte is an efficient binder to preserve the electrode architecture upon cycling.
The Na/PVdF/S cells were composed of solid sodium, sulfur, and polyvinylidene fluoride–hexafluoropropene (PVdF) gel polymer electrolyte. The PVdF polymer electrolyte was prepared form tetraglyme ...plasticizer and NaCF
3
SO
3
salt, and its electrochemical properties were studied using CV and impedance analysis. The interfacial resistance between sodium and polymer electrolyte increase with storage time, which might be associated with passivation layer. Solid-state sodium/sulfur cell using a PVdF gel polymer electrolyte has been tested. The Na/PVdF/S cell with 0.288 mA cm
−2
shows a high discharge capacity of 392 mAh g
−1
and 36 mAh g
−1
after 20 cycles. The cycle performance of Na/GPE/S cell operating at 25 °C is worse than Na/S cell at a high temperature.
The lithium/sulfur cell is very attractive because of its high theoretical specific capacity and low production cost. The sulfur electrode is prepared from sulfur, with carbon as an electronic ...conductor and PEO as an ionic conductor. We changed the carbon content of a 50 wt.% sulfur electrode from 10 wt.% to 40 wt.%. The lithium/PEO/sulfur cell showed two plateau potential regions (2.4 V, 2.1 V) and high discharge capacity, i.e., 1484 mAh/g (88% utilization) for optimum composition. The discharge capacity decreased drastically by charge-discharge cycling. The degradation rate as well as the first discharge capacity depended on the composition of the sulfur electrode. The optimum composition of the 50 wt.% sulfur electrode was 30 wt.% carbon and 20% PEO.PUBLICATION ABSTRACT
The lithium/sulfur cell is very attractive because of its high theoretical specific capacity and low production cost. The sulfur electrode is prepared from sulfur, with carbon as an electronic ...conductor and PEO as an ionic conductor. We changed the carbon content of a 50 wt.% sulfur electrode from 10 wt.% to 40 wt.%. The lithium/PEO/sulfur cell showed two plateau potential regions (2.4 V, 2.1 V) and high discharge capacity, i.e., 1484 mAh/g (88 % utilization) for optimum composition. The discharge capacity decreased drastically by charge-discharge cycling. The degradation rate as well as the first discharge capacity depended on the composition of the sulfur electrode. The optimum composition of the 50 wt.% sulfur electrode was 30 wt.% carbon and 20 % PEO.
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