New insights into the electrode mechanism of lithium sulfur batteries via air-free post-test analysis

Abstract

Effects of the volume expansion and shrinkage of Li2S cathodes on electrochemical cycle life are investigated via post-test analysis without exposure to air. The engineered electrodes that confine volume changes within micro-reactors have significantly longer life than the electrodes without the micro-reactor structure, providing the first unambiguous evidence of the importance of confining volume changes for improved battery performance.

A New Graphitic Nitride and Reduced Graphene Oxide-Based Sulfur Cathode for High-Capacity Lithium-Sulfur Cells

“…In the past two decades, extensive research has been conducted to address the insulating nature of sulfur by incorporating it in porous carbons [6][7][8][9][10][11] and carbon nanotubes [12][13][14][15]. Designs with reduced graphene oxide (RGO) and graphene [16][17][18][19][20][21][22][23][24] have also been explored extensively. While the carbon-based cathode structures provide good electrical conductivity and room for volume expansion, the complete retention of lithium polysulfides (LiPSs) in the cathode structure is difficult because of the lack of poor interactions (carbon is nonpolar while LiPSs are polar).…”

First-Principles Investigation of the Anchoring Behavior of Pristine and Defect-Engineered Tungsten Disulfide for Lithium–Sulfur Batteries

“…The reduction of the long-chain polysulfides further leads to insoluble reaction products such as Li 2 S 2 and Li 2 S, which deposit and passivate the electrode surfaces. ,, The passivation layer increases cell resistance and causes active mass loss that aggravates the cycling capability and expedites capacity fading. Additionally, significant volume changes of sulfur materials during charging and discharging cause pulverization and mechanical failure of the cathode material. , …”

“…Additionally, significant volume changes of sulfur materials during charging and discharging cause pulverization and mechanical failure of the cathode material. 11,12 To improve the conductivity of sulfur cathode and to adsorb lithium polysulfides (LiPSs), various kinds of carbon materials with good electric conductivity and large surface areas are widely used. 5,13 However, the LiPSs adsorb on nonpolar carbon materials only through weak physical interactions and can easily detach from the cathode to dissolve into the electrolytes.…”

Li3BN2 as a Transition Metal Free, High Capacity Cathode for Li‐ion Batteries

“…To increase the energy density beyond what the redox of cationic species can offer, oxygen redox in intercalation oxides has been explored . Furthermore, non‐intercalation materials such as S and Li 2 S cathodes have also been studied . These S‐based cathode materials have very high theoretical capacities (>1,000 mA h g −1 ), but suffer from large volume change (∼80 %), polysulfide dissolution and insulating problems, leading to poor cycling life and low capacity retention .…”

“…Furthermore, non‐intercalation materials such as S and Li 2 S cathodes have also been studied . These S‐based cathode materials have very high theoretical capacities (>1,000 mA h g −1 ), but suffer from large volume change (∼80 %), polysulfide dissolution and insulating problems, leading to poor cycling life and low capacity retention . As such, new types of cathode materials with high capacities and high energy densities are urgently needed to meet the need for vehicle electrification.…”