Trends in Chemistry

Trends in Chemistry

Volume 2, Issue 11, November 2020, Pages 1020-1033
Journal home page for Trends in Chemistry

Review
Accelerating Redox Kinetics of Lithium-Sulfur Batteries

https://doi.org/10.1016/j.trechm.2020.09.001Get rights and content

Highlights

  • It is critical to suppress the shuttle effect and increase sulfur utilization through designing host materials that can not only adsorb lithium polysulfides (LiPSs) but also catalyze their conversion.

  • Catalytic materials for accelerating the sulfur redox reaction include metal-free polar materials, transition-metal compounds, and metals.

  • The design of catalytic materials should consider the balance of LiPS trapping ability, surface reactivity, diffusivity of lithium ions and LiPSs, and electrical conductivity.

Lithium-sulfur (Li-S) batteries exhibit great promise for next-generation energy storage due to their high theoretical energy density and low cost. However, their practical application is largely hindered by the shuttle effect. Although previous studies on the adsorption of lithium polysulfides (LiPSs) have achieved significant progress, simple adsorption cannot fundamentally eliminate the shuttle effect. Physical and chemical confinement are useful to anchor LiPSs to some extent, but these are not effective for utilizing the blocked intermediates. Accordingly, accelerating polysulfide redox kinetics is crucial to radically mitigate the shuttle effect and increase sulfur utilization. Herein, recent advances in catalysts for boosting redox kinetics of Li-S batteries are reviewed. We also provide prospects on the design of more efficient catalysts for Li-S batteries.

Section snippets

Catalytic Effect in Lithium-Sulfur Batteries

The rapid development of electric vehicles is driving an ever increasing demand for rechargeable batteries with higher energy density and lower cost than that of current lithium-ion batteries [1., 2., 3.]. Among alternative battery technologies, lithium-sulfur (Li-S) batteries are regarded as one of the most promising systems for next-generation energy storage owing to their high theoretical energy density (2500 Wh kg–1), low cost, and low environmental impact [4., 5., 6., 7.]. Despite these

Metal-Free Polar Materials

Over the past decade, metal-free catalysts have attracted extensive research interests in both fuel cells and water splitting owing to their low cost and relatively high catalytic activity [44., 45., 46.]. Due to similar requirements of high catalytic activity for polysulfide conversion, metal-free catalysts have also been applied in Li-S batteries in recent years. Among the metal-free polar materials, heteroatom-doped carbon nanostructures are the most common catalysts. Using density

Transition-Metal Oxides

Transition-metal compounds have also been applied as catalysts for Li-S batteries. In 2015, Nazar and coworkers proposed that MnO2 can oxidize polysulfides to form thiosulfate on the surface and thiosulfate can function as a redox mediator to anchor long-chain LiPSs and trigger conversion to lithium sulfides via disproportionation reactions (Figure 3A) [52]. This catalytic mechanism was different from previous studies and the resultant MnO2/S composite demonstrated stable cycling performance

Transition-Metal Sulfides

Metal sulfides have been widely used as electrocatalysts for water splitting [56., 57., 58.]. In Li-S batteries, apart from their strong chemical anchoring ability for LiPSs, recent studies have found that metal sulfides have superior catalytic activity for polysulfide conversion. Zhang and coworkers reported that sulfiphilic CoS2 can provide strong adsorption and catalytic sites for LiPS conversion (Figure 4A) [59]. Symmetric cells with CoS2/graphene electrodes showed much higher current

Transition-Metal Nitrides

Metal nitrides have been applied as catalysts for Li-S batteries due to their higher electrical conductivity compared with their metal oxide and metal sulfide counterparts. Ding and coworkers found that TiN can effectively reduce the potential barrier for Li2S oxidation (Figure 5A) [64]. It was also found that TiN can efficiently catalyze the reduction of LiPSs. DFT calculations revealed that the faster polysulfide conversion on TiN surfaces is mainly ascribed to its stronger chemical

Transition-Metal Carbides

Transition-metal carbides have been explored as efficient redox mediators for the conversion between S and Li2S [67., 68., 69., 70., 71., 72.]. Recently, Wu and coworkers reported tungsten carbide materials embedded in a metal-organic framework (MOF)-derived carbon (WxC/md-C) via the pyrolysis of phosphotungstic acid (PTA)-functionalized MOFs (Figure 6A) [70]. The in situ formed precursors not only suppress the vaporization of the carbon source, but also favor the generation of WC and W2C

Transition-Metal Phosphides

Compared with the above-mentioned metallic compounds, transition-metal phosphides have the merits of metallic character and facile synthesis [73]. Moreover, metal phosphides feature both high LiPS absorption ability and low Li2S dissociation energies, which are regarded as the most important factors to facilitate the redox kinetics of Li-S batteries [74]. In an early study, Tao and colleagues reported a facile synthetic approach to prepare metal phosphides (Ni2P, Co2P, Fe2P) simply by annealing

Metal Nanoparticles, Clusters, and Single Atoms

Recently, metal nanoparticles, clusters, and single atoms have drawn extensive attention in the research field of electrocatalysis for applications such as water splitting [77], CO2 reduction [78,79], N2 fixation [80], and fuel cells [81,82]. This concept has also been introduced to Li-S batteries. Salem and coworkers first reported that the uniform distribution of Pt nanoparticles on graphene can reduce LiPS redox overpotential and deliver a 40% enhancement in the specific capacity over

Other Metal-Based Catalysts

Besides the typical metal-based catalysts discussed earlier, some metal borides and MOFs also show potential catalytic activity for the redox reactions in Li-S batteries. Nazar and coworkers reported that the lightweight superconductor MgB2 can serve as a metallic sulfur host with both high conductivity and superior LiPS confinement [89]. By using DFT calculations, they found that the borides are unique in that both B- and Mg-terminated surfaces bond exclusively with the Sx2– anions and not the

Concluding Remarks

Over the past 5 years, the efforts devoted to improving sluggish LiPS redox kinetics have generated rich knowledge on how to design catalysts for Li-S batteries. In this review, we highlighted recent significant progress on materials with both strong LiPS absorption ability and boosted catalytic effect, including metal-free polar materials, transition-metal compounds, and metals. An ideal catalyst for Li-S batteries should satisfy the following prerequisites:

  • (i)

    Favorable electrical conductivity

Acknowledgments

This work was financially supported by the Australian Renewable Energy Agency project (ARENA 2014/RND106), Australian Research Council (ARC) Discovery projects (DP170100436, DP180102297, and DP200101249), ARC Discovery Early Career Researcher Award (DECRA DE170101009), UTS Early Career Researcher Grant (ECRGS PRO16-1304), and UTS Chancellor’s Postdoctoral Research Fellowship (PRO16-1893).

References (90)

  • M. Armand et al.

    Building better batteries

    Nature

    (2008)
  • J. Liu

    Pathways for practical high-energy long-cycling lithium metal batteries

    Nat. Energy

    (2019)
  • Y. Cao

    Bridging the academic and industrial metrics for next-generation practical batteries

    Nat. Nanotech.

    (2019)
  • P.G. Bruce

    Li-O2 and Li-S batteries with high energy storage

    Nat. Mater.

    (2012)
  • J. Xu

    Updated metal compounds (MOFs, S, OH, N, C) used as cathode materials for lithium-sulfur batteries

    Adv. Energy Mater.

    (2018)
  • G. Li

    Lithium-sulfur batteries for commercial applications

    Chem

    (2018)
  • R.F. Service

    Lithium-sulfur batteries poised for leap

    Science

    (2018)
  • A. Manthiram

    Rechargeable lithium-sulfur batteries

    Chem. Rev.

    (2014)
  • Q. Pang

    Advances in lithium-sulfur batteries based on multifunctional cathodes and electrolytes

    Nat. Energy

    (2016)
  • Y. Chen

    Co–Fe mixed metal phosphide nanocubes with highly interconnected-pore architecture as an efficient polysulfide mediator for lithium-sulfur batteries

    ACS Nano

    (2019)
  • X. Liu

    Nanostructured metal oxides and sulfides for lithium-sulfur batteries

    Adv. Mater.

    (2017)
  • Z.W. Seh

    Designing high-energy lithium-sulfur batteries

    Chem. Soc. Rev.

    (2016)
  • X. Gao

    Strong charge polarization effect enabled by surface oxidized titanium nitride for lithium-sulfur batteries

    Commun. Chem.

    (2019)
  • H.-J. Peng

    A review of flexible lithium-sulfur and analogous alkali metal–chalcogen rechargeable batteries

    Chem. Soc. Rev.

    (2017)
  • X. Ji

    A highly ordered nanostructured carbon–sulphur cathode for lithium-sulphur batteries

    Nat. Mater.

    (2009)
  • N. Jayaprakash

    Porous hollow carbon@sulfur composites for high-power lithium-sulfur batteries

    Angew. Chem. Int. Ed.

    (2011)
  • G. Zheng

    Hollow carbon nanofiber-encapsulated sulfur cathodes for high specific capacity rechargeable lithium batteries

    Nano Lett.

    (2011)
  • R. Fang

    The regulating role of carbon nanotubes and graphene in lithium-ion and lithium-sulfur batteries

    Adv. Mater.

    (2019)
  • Z.W. Seh

    Sulphur-TiO2 yolk-shell nanoarchitecture with internal void space for long-cycle lithium-sulphur batteries

    Nat. Commun.

    (2013)
  • Z. Li

    A sulfur host based on titanium monoxide@carbon hollow spheres for advanced lithium-sulfur batteries

    Nat. Commun.

    (2016)
  • J. Xu

    MOF-derived porous N-Co3O4@N-C nanododecahedra wrapped with reduced graphene oxide as a high capacity cathode for lithium-sulfur batteries

    J. Mater. Chem. A

    (2018)
  • Y. Chen

    Self-standing sulfur cathodes enabled by 3D hierarchically porous titanium monoxide-graphene composite film for high-performance lithium-sulfur batteries

    Nano Energy

    (2018)
  • X. Tao

    Balancing surface adsorption and diffusion of lithium-polysulfides on nonconductive oxides for lithium-sulfur battery design

    Nat. Commun.

    (2016)
  • T. Chen

    Metallic and polar Co9S8 inlaid carbon hollow nanopolyhedra as efficient polysulfide mediator for lithium-sulfur batteries

    Nano Energy

    (2017)
  • T. Chen

    Self-templated formation of interlaced carbon nanotubes threaded hollow Co3S4 nanoboxes for high-rate and heat-resistant lithium-sulfur batteries

    J. Am. Chem. Soc.

    (2017)
  • J. Pu

    Multifunctional Co3S4@sulfur nanotubes for enhanced lithium-sulfur battery performance

    Nano Energy

    (2017)
  • Z. Cheng

    Elastic sandwich-type rGO-VS2/S composites with high tap density: structural and chemical cooperativity enabling lithium-sulfur batteries with high energy density

    Adv. Energy Mater.

    (2018)
  • Z. Xiao

    Sandwich-type NbS2@S@I-doped graphene for high-sulfur-loaded, ultrahigh-rate, and long-life lithium-sulfur batteries

    ACS Nano

    (2017)
  • X. Xiao

    Two-dimensional arrays of transition metal nitride nanocrystals

    Adv. Mater.

    (2019)
  • L. Ma

    Porous-shell vanadium nitride nanobubbles with ultrahigh areal sulfur loading for high-capacity and long-life lithium-sulfur batteries

    Nano Lett.

    (2017)
  • J. Song

    Rational design of free-standing 3D porous MXene/rGO hybrid aerogels as polysulfide reservoirs for high-energy lithium-sulfur batteries

    J. Mater. Chem. A

    (2019)
  • W. Bao

    Facile synthesis of crumpled nitrogen-doped MXene nanosheets as a new sulfur host for lithium-sulfur batteries

    Adv. Energy Mater.

    (2018)
  • Z.W. Zhang

    Heterogeneous/homogeneous mediators for high-energy-density lithium-sulfur batteries: progress and prospects

    Adv. Funct. Mater.

    (2018)
  • M. Zhang

    Adsorption-catalysis design in the lithium-sulfur battery

    Adv. Energy Mater.

    (2020)
  • D. Su

    Toward high performance lithium-sulfur batteries based on Li2S cathodes and beyond: status, challenges, and perspectives

    Adv. Funct. Mater.

    (2018)
  • G. Zhou

    Catalytic oxidation of Li2S on the surface of metal sulfides for Li-S batteries

    Proc. Nat. Acad. Sci. U. S. A.

    (2017)
  • M.R. Kaiser

    Lithium sulfide-based cathode for lithium-ion/sulfur battery: recent progress and challenges

    Energy Storage Mater.

    (2019)
  • L. Guan

    Intrinsic defect-rich hierarchically porous carbon architectures enabling enhanced capture and catalytic conversion of polysulfides

    ACS Nano

    (2020)
  • Z. Yu

    Boosting polysulfide redox kinetics by graphene-supported Ni nanoparticles with carbon coating

    Adv. Energy Mater.

    (2020)
  • D. Zhang

    Catalytic conversion of polysulfides on single atom zinc implanted MXene toward high-rate lithium-sulfur batteries

    Adv. Funct. Mater.

    (2020)
  • Z. Sun

    Catalytic polysulfide conversion and physiochemical confinement for lithium-sulfur batteries

    Adv. Energy Mater.

    (2020)
  • R. Li

    Sandwich-like catalyst-carbon-catalyst trilayer structure as a compact 2D host for highly stable lithium-sulfur batteries

    Angew. Chem. Int. Ed.

    (2020)
  • X. Gao

    Cobalt-doped SnS2 with dual active centers of synergistic absorption-catalysis effect for high-S loading Li-S batteries

    Adv. Funct. Mater.

    (2019)
  • Y. Chen

    Low-temperature and one-pot synthesis of sulfurized graphene nanosheets via in situ doping and their superior electrocatalytic activity for oxygen reduction reaction

    J. Mater. Chem. A

    (2014)
  • X. Liu et al.

    Carbon-based metal-free catalysts

    Nat. Rev. Mater.

    (2016)

    • Cited by (0)

    3

    These authors contributed equally to this work

    View full text
    © 2020 Elsevier Inc. All rights reserved.