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Schematics of the blood coagulation and LiPS clotting mechanisms a In mammals, when an injury happens in a vessel wall, the platelets become activated, triggering the formation of thrombus to stanch bleeding. After the wound is healed, thrombolysis occurs spontaneously. b Diffusion of LiPS in Li–S batteries can be effectively restrained by a recoverable protective clotting layer formed in situ from the reaction between dissolved LiPS and LiPS clotting factors at the electrode–electrolyte interface during the discharge/charge process.
Source publication
Encapsulation strategies are widely used for alleviating dissolution and diffusion of polysulfides, but they experience nonrecoverable structural failure arising from the repetitive severe volume change during lithium−sulfur battery cycling. Here we report a methodology to construct an electrochemically recoverable protective layer of polysulfides...
Citations
... The lithium-sulfur (Li-S) battery has emerged as one of the most promising candidates for next-generation rechargeable batteries owing to its ultrahigh theoretical energy density of 2567 Wh kg −1 and outstanding advantages of nontoxicity and natural abundance for sulfur active materials [1][2][3][4][5]. However, the sluggish reaction kinetics of active materials [6,7] and notorious shuttling of soluble lithium polysulfides (LiPSs) intermediates [6,8] severely hinder the practical applications of Li-S batteries, which results in low sulfur utilization, rapid capacity fading and shortened cycle life [9,10]. ...
... The diffusion characteristics of lithium ions can be evaluated by conducting CV tests according to the Randles-Sevcik equation [45,46]. I p = (2.69 × 10 5 )n 1.5 AD 0. 5 Li ...
The lithium-sulfur (Li-S) battery possessing an ultrahigh theorical energy density has emerged as a promising rechargeable battery system. However, the practical applications of Li-S batteries are severely plagued by the sluggish reaction kinetics of sulfur species and notorious shuttling of soluble lithium polysulfides (LiPSs) intermediates that result in low sulfur utilization. The introduction of functional layers on separators has been considered as an effective strategy to improve the sulfur utilization in Li-S batteries by achieving effective regulation of LiPSs. Herein, a promising self-assembly strategy is proposed to achieve the low-cost fabrication of hollow and hierarchically porous Fe3O4 nanospheres (p-Fe3O4-NSs) assembled by numerous extremely-small primary nanocrystals as building blocks. The rationally-designed p-Fe3O4-NSs are utilized as a multifunctional layer on the separator with highly efficient trapping and conversion features toward LiPSs. Results demonstrate that the nanostructured p-Fe3O4-NSs provide chemical adsorption toward LiPSs and kinetically promote the mutual transformation between LiPSs and Li2S2/Li2S during cycling, thus inhibiting the LiPSs shuttling and boosting the redox reaction kinetics via a chemisorption-catalytic conversion mechanism. The enhanced wettability of the p-Fe3O4-NSs-based separator with the electrolyte enables fast transportation of lithium ions. Benefitting from these alluring properties, the functionalized separator with p-Fe3O4-NSs endows the battery with an admirable rate performance of 877 mAh g-1 at 2 C, an ultra-durable cycling performance of up to 2176 cycles at 1 C, and a promising areal capacity of 4.55 mAh cm-2 under high-sulfur-loading and lean-electrolyte conditions (4.29 mg cm-2, electrolyte/ratio: 8 μL mg-1). This study will offer fresh insights on the rational design and low-cost fabrication of multifunctional separator to strengthen electrochemical reaction kinetics via regulating LiPSs conversion for developing efficient and long-life Li-S battery.
... On the other hand, several research groups have studied how to encapsulate the sulfur in the cathode [23][24][25] and it has been proved that some ILs, either as electrolytes dissolved in organic solvents or as pure solvents, improve the performance of Li-S batteries [26,27], but it has not been studied the effect of the nature of the ILs on the reaction mechanisms and on the formal redox potentials (E 0' ) of redox reactions of elemental sulfur. 4 ], and TBAPF 6 as electrolytes, and PEDOT as an electrocatalyst during the reduction of elemental sulfur in either DMSO or CH 3 CN. ...
The commercial use of Lithium-sulfur batteries has been limited by their short service life due to the shuttle effect of polysulfides, which is due to the transport of polysulfides towards the anode and the formation of highly resistive deposits that passivate the electrodes. This problem can be solved by decreasing the transport of these species from the cathode to the anode and simultaneously improving the kinetics of electron transfer reactions. This work studies by electrochemical impedance spectroscopy and cyclic and ac voltammetry the redox reactions of elemental sulfur in either acetonitrile (CH3CN) or dimethyl sulfoxide (DMSO) using as a working electrode either pristine glassy carbon (GC) or GC modified with a thin film of poly-3,4-ethylenedioxythiophene (GC-PEDOT) as working electrodes. Tetrabutylammonium hexafluorophosphate (TBAPF6), 1-Butyl-3-methylimidazolium tetrafluoroborate ([Bmim][BF4]) and 1-Butyl-3-methylimidazolium triflate ([Bmim][OTf]) were investigated as electrolytes. It was found that the kinetics of the first reduction reaction of S8 on GC is much faster in CH3CN than in DMSO and when [Bmim][OTf] is used as an electrolyte. On the other hand, it was found that PEDOT is electrocatalytic for the first reduction reaction of elemental sulfur. Finally, by encapsulating the sulfur in PEDOT it is possible to increase the retention of the sulfur species inside PEDOT upon redox cycling if pure ionic liquids are used as electrolytes.
... To overcome these shortcomings, many efforts have been devoted to developing an advanced sulfur host that offers trapping interaction towards soluble LiPSs. For instance, various nonpolar carbonaceous matrices with high electronic conductivity, such as mesoporous carbon, graphene, and carbon nanotubes (CNTs) have been broadly combined with sulfur to increase the electronic conductivity of cathode as well as to fix polysulfides through physical confinement [14][15][16][17]. However, the weak force between the polar polysulfides and nonpolar carbonaceous matrices results in an easy leakage of polysulfides from the cathode, causing the shuttle effect. ...
The shuttle effect and slow redox kinetics of sulfur cathode are the most significant technical challenges to the practical application of lithium-sulfur (Li-S) battery. Herein, a novel zwitterionic covalent organic framework (ZW-COF) wrapped onto carbon nanotubes (CNTs), labeled as [email protected], is developed by a reversible condensation reaction of 1,3,5-benzenetricarboxaldehyde (BTA) and 3,8-diamino-6-phenylphenanthridine (DPPD) with CNTs as a template and a subsequently one-step post-synthetic grafting reaction with 1,3-propanesultone. The experimental results showed that, after loading active material sulfur, zwitterionic [email protected] can effectively suppress the shuttle effect of the soluble lithium polysulfides (LiPSs) in Li-S batteries, and exhibits better cycling behavior than the as-developed neutral [email protected] Specifically, the as-obtained [email protected] based sulfur cathode can maintain a discharge capacity of 944 mAh g⁻¹ after 100 cycles, while that of [email protected] based sulfur cathode drops to (665 mAh g⁻¹) after 100 cycles. Moreover, the [email protected] based sulfur cathode delivers an attractive prolonged cycling behavior with a low capacity decay rate of 0.046% per cycle at 1 C. This work sheds new light on rational selection and design of functionalized COFs based sulfur cathode in the Li-S battery.
... The MB-PW 12 samples in different redox states all present one peak of Li 1s at around 55.5 eV, which is attributed to Li-O and Li-N bond. 32 More specifically, the content of lithium ions in MB-PW 12 varies with different redox potentials. The samples of MB-PW 12 in different redox state were digested in HNO 3 , and the Li content was measured by ICP. ...
For any electrode process, the active species reaching the reaction sites of the electrode surface will ultimately become a controlling step, and this depends on the diffusion layer and its thickness. The diffusion layer, however, is not readily modified other than by introducing vigorous stirring. In lithium-ion-based energy storage, the supply of lithium ion to the reaction sites is certainly a rate-limiting step. Herein, we report an unusual type of “forced convection” by introducing a functionalized molecule in the electrode to break the traditional diffusion limit resulting in an alternative mode of mass transfer. The functionalized molecule, methylene blue phosphotungstate (MB-PW12), is designed with multiple redox properties that can “adsorb” and “release” lithium ion during its redox processes. By implanting the MB-PW12 in sulfur cathode matrix, forced lithium-ion flux can be realized, and this also favors polysulfides adsorption and catalysis, thus boosting the sulfur conversion reactions.
... Usually, Li 2 S cathodes undergo a similar redox pathway with sulfur cathode in Li-S batteries, where soluble Li polysulfides (LiPS) with various chain lengths act as the redox intermediates to oxidize the Li 2 S to sulfur upon charge and vice versa (17). In this process, the reversibility of Li 2 S cathode and the cells is deteriorated by LiPS leaking into LEs and their shuttling to contaminate the anode (18). Various efforts including physical trapping, chemical adsorption, electrocatalysis, and applying electrolyte additives or gel electrolytes have been devoted to reducing LiPS diffusion in working cells (19)(20)(21)(22)(23)(24). ...
Safety risks stem from applying extremely reactive alkali metal anodes and/or oxygen-releasing cathodes in flammable liquid electrolytes restrict the practical use of state-of-the-art high-energy batteries. Here, we propose a intrinsically safe solid-state cell chemistry to satisfy both high energy and cell reliability. An all-solid-state rechargeable battery is designed by energetic yet stable multielectron redox reaction between Li2S cathode and Si anode in robust solid-state polymer electrolyte with fast ionic transport. Such cells can deliver high specific energy of 500 to 800 Wh kg−1 for 500 cycles with fast rate response, negligible self-discharge, and good temperature adaptability. Integrating intrinsic safe cell chemistry to robust cell design further guarantees reversible energy storage against extreme abuse of overheating, overcharge, short circuit, and mechanical damage in the air and water. This work may shed fresh insight into bridging the huge gap between high energy and safety of rechargeable cells for feasible applications and recycle.
... The areal capacity can reach 8.2 mAh cm −2 at the beginning and maintain 5.9 mAh cm −2 after 70 cycles at 0.1 C. The capacity fluctuations could derive from the volume fluctuations and redistribution of sulfur during cycling. 48 The electrochemical properties of the battery with Co−N 2 /PP are remarkable compared to previous related works (Table S3 in the Supporting Information). These results confirm that Co−N 2 efficiently immobilizes LiPSs and catalyzes their conversion. ...
... At the same time, more GBs on the surface can provide more Li + pathways and active sites to accelerate the Li 2 S dissociation. Thus, the battery with RGB-MN/CNT interlayers showed decreased overpotential for Li 2 S oxidation in the following cycles [43][44][45]. ...
Catalysis is a fundamental solution in suppressing the shuttling of lithium polysulfides (LiPSs), which is essential to the practical applications of lithium-sulfur batteries with high energy density. However, the uncontrollable deposition of electronic and ionic insulative Li2S always passivates the catalyst surface for the continuous LiPS conversion. Herein, we propose an effective method to regulate Li2S deposition to avoid the catalyst surface passivation by introducing grain boundaries (GBs) in the catalyst. Hollow microspheres composed of MoN-Mo2N heterostructure with abundant and highly accessible GBs were prepared as the models. The results show GBs act as the two-dimensional nucleation sites, guiding the fast nucleation and three-dimensional deposition of Li2S around them, avoiding the formation of dense Li2S coating on their surface. Thus, the high capacity Li2S deposition with enhanced conversion kinetics was achieved. The interlayer composed of the above catalyst and carbon nanotube effectively suppresses the shuttling of LiPSs and promotes their fast conversion, leading to a low capacity decay of 0.049% per cycle at 1 C for 800 cycles for the assembled battery. With a higher sulfur loading of 4.7 mg cm⁻² under 0.5 C, high capacity retention of 77.2% after 200 cycles could also be achieved.
... 5,6 Nevertheless, there are still a variety of obstacles to plague Li-S batteries to be commercialized, such as insulation of sulfur (5 × 10 −30 S cm −1 at 25°C), 7 a large volume fluctuation (80%) 8 and the "shuttle effect" of long chain lithium polysulfide (Li 2 S x , 4 ⩽ × ⩽8). 9 Therein, Li 2 S x is soluble in the etherbased electrolyte around the cathode, and it can pass through the separator and arrive at the anode surface because of the concentration difference. The dissolved Li 2 S x is chemically reduced [Eq. ...
... Two pairs of theoretical reduction peaks, 2.35 V and 2.10 V vs Li + /Li, is shown in the galvanostatic charge-discharge curves of 35 mg ml −1 showed. 9 Two main steps of electrochemical reduction reaction are not affected by CIPs. In addition, there is an reduction of over-potential (η), which representing the fast reaction kinetic contributed by the electrocatalysis of CIPs. ...
Lithium sulfur (Li-S) batteries are considered one of the most promising energy storage devices due to their high specific capacity, pollution-free reactant, and low cost. However, the “shuttle effect” of lithium polysulfide (Li2S x ) leads to a fast capacity decay and poor cycle life. Here, the magnetorheological effect (MRE) is first applied in Li-S batteries and a magnetic control electrolyte is designed by introducing carbonyl iron powders (CIPs) to improve the performance of Li-S batteries. According to adsorption bonding theory, the binding energy of Fe site with Li2S4 is up to 2.68 eV via discrete Fourier transform (DFT) calculation. After coupling an external magnetic field, the uniform distribution of CIPs avoids the accumulation on the cathode surface. The induced magnetic field of spherical particles captures dissolved S x ²⁻ effectively by Lorenz force, which is confirmed by adsorption experiments. These magnetized particles form a magnetic shield layer in the electrolyte and alleviate the “shuttle effect.” At 0.2 C, the initial specific capacity reaches 1296 mAh g⁻¹. Magnetic control electrolyte provides not only a novel insight but also creates a new possibility for mitigating the “shuttle effect” thereby promoting performance of Li-S batteries.
... However, high efficiency energy storage device like electric vehicles not only carried out at room temperature, but also used to the traveled region both in high and low temperatures on earth, it is highly requiring to enable the Li-S batteries work in the relative wide temperature range to stimulate the booming fields [4][5][6] . However, the wide temperature application of Li-S battery is seriously chained by the slow conversion kinetics, severe dissolution and unbridled shuttle of intermediate polysulfide during the electrochemical cycling [7][8][9] , thus initial discharge performance of 874 mA h g − 1 with the CE of 71.3%, but also exhibited a capacity retention of 82.2% under low temperature of − 25 °C [21] . Dong et al. reported a composite host consisted of graphene supported BN nanosheet (BN/G) to enhance the adsorption for polysulfides in a wide temperature range. ...
Suppressing the dissolution and accelerating conversion kinetics of intermediate polysulfides are central to the practical usage of lithium−sulfur (Li–S) battery in a wide temperature range. Herein, an atomic engineering strategy is innovatively proposed to constructing a sulfur host consisting of chemical-anchoring zinc atomic cluster within double layer N-doped carbon matrix (ZnAC[email protected]) for addressing concerns. The as-prepared ZnAC[email protected]@S can deliver capacity as high as 1451 mAh g⁻¹ at 0.2 C with electrolyte/sulfur ratio (E/S ratio) of 5.5 μL mg⁻¹ and maintain 749 mAh g⁻¹ after 1200 cycles (fading rate of 0.021% per cycle) at 5 C. Remarkably, the reversible capacity holds 627 mAh g⁻¹ at 0.2 C at the −25 ℃. By a further combination analysis of electron holography (EH) and geometry phase analysis (GPA), the outstanding performance is revealed to be mainly traced to synergistic effect of the polarity N-doped multi-layer carbon matrix and internal periodical charge field induced by atomic strain, greatly enhancing the capability towards on the immobilization and conversion of intermediate polysulfides. More importantly, such an interplay also renders the strongly coupled cathode achieve a high area specific capacity of 8.71 mAh cm⁻² even the area sulfur loading obtain to 7.34 mg cm⁻². This atomic-level engineering strategy might shed light on the novel insights on the design of high performance for sulfur hosts.
... However, it is plagued with two key barriers that limit its applications: interfacial instability of lithium-metal anode and shuttling of soluble intermediate polysulfides of the sulfur cathode 1 . To tackle these problems, several techniques have been proposed, including: electrode modification, such as designing structured Li-metal anodes [2][3][4] ; confining S within porous carbon or other nano-architectures with tailored surface [5][6][7] ; electrolyte modification, such as using redox mediators and novel lithium salt/ionic liquid electrolyte [8][9][10][11][12][13][14] ; electrode-electrolyte interface modification 15 , such as constructing solid-electrolyte interphase (SEI) on the Li-metal surface [16][17][18][19][20][21][22][23] ; and protective layers on the S cathode 24,25 . These efforts are directly related to the electrodeelectrolyte interfaces [26][27][28][29][30][31] , which have profound effect on battery performance. ...
... .[1][2][3][4][7][8][9][10][12][13][14]16,17,20, and 21 are provided as a Source Data file. The other data support the findings of this study are available from the corresponding author upon request. ...
The interfacial instability of the lithium-metal anode and shuttling of lithium polysulfides in lithium-sulfur (Li-S) batteries hinder the commercial application. Herein, we report a bifunctional electrolyte additive, i.e., 1,3,5-benzenetrithiol (BTT), which is used to construct solid-electrolyte interfaces (SEIs) on both electrodes from in situ organothiol transformation. BTT reacts with lithium metal to form lithium 1,3,5-benzenetrithiolate depositing on the anode surface, enabling reversible lithium deposition/stripping. BTT also reacts with sulfur to form an oligomer/polymer SEI covering the cathode surface, reducing the dissolution and shuttling of lithium polysulfides. The Li–S cell with BTT delivers a specific discharge capacity of 1,239 mAh g ⁻¹ (based on sulfur), and high cycling stability of over 300 cycles at 1C rate. A Li–S pouch cell with BTT is also evaluated to prove the concept. This study constructs an ingenious interface reaction based on bond chemistry, aiming to solve the inherent problems of Li–S batteries.
