A Lithium‐Sulfur Battery with a High Areal Energy Density

Abstract

5359 www.MaterialsViews.com wileyonlinelibrary.com density, which is approximately 6.6 times larger than that of the current intercalationbased LIBs (≈387 Wh kg −1 ). [5][6][7][8] Remarkably, recent research efforts have been successful in resolving the chronic technical challenges associated with sulfur electrodes, especially dissolution of lithium polysulfi des and low electric conductivity of elemental sulfur. [9][10][11][12] The representative solutions along this direction include sulfur-carbon composite structures that minimize sulfur exposure to electrolyte, [ 5,13 ] surface coating of active particles, [ 7,[14][15][16] engagement of allotropic sulfur, [ 17,18 ] and use of solid-state electrolytes [ 19 ] and electrolyte additives. [ 20,21 ] Although the improved cycle lives based on these approaches represent considerable progresses in the area of Li-S batteries, it should be noted that the most critical issue related to Li metal anodes still remains unaddressed: upon repeated charge and discharge, Li dendrites grow on the surface of the Li metal anode, which triggers multiple mechanisms for rapid capacity fading. The electrolyte becomes decomposed successively along the Li dendrite surfaces, which destabilizes the electrode-electrolyte interface and also increases the resistance (or overpotential) leading to continuous capacity decay. The electrolyte could be eventually exhausted. The dendrite growth could also promote short circuits between both electrodes, and thus resulting in severe safety hazard. [ 22 ] An additional but very critical hurdle related to the Li dendrite growth is that the dendrite growth becomes accelerated with areal current density. [22][23][24][25][26] Hence, the increase in the areal capacity of sulfur electrode (or the areal mass loading of sulfur active material) would amplify the problems originating from Li dendrites. Likewise, the dissolution of the fatal lithium polysulfi des would also be amplifi ed under the increased areal capacity. The demonstration of improved cycle lives from most of recent sulfur electrode designs, in turn, implies that the cycling tests were conducted with moderate mass loadings of the sulfur active materials. Therefore, in order to exalt Li-S batteries to more practical technology, more systematic approaches need to be engaged to resolve the issues from both sides of electrodes.With purpose of developing Li-S cells with high areal energy densities, herein, we have adopted or discovered the key cell components (sulfur electrode, separator, and electrolyte) in a way that Li dendrite formation and polysulfi de dissolution are minimized even at a practically viable loading of sulfur active material (≈17 mg cm −2 , the mass of sulfur-carbon composite). The synergistic outcomes from smart engineering of eachThe battery community has recently witnessed a considerable progress in the cycle lives of lithium-sulfur (Li-S) batteries, mostly by developing the electrode structures that mitigate fatal dissolution of lithium polysulfi des. Nonetheless, most of the ...

Critical Link between Materials Chemistry and Cell-Level Design for High Energy Density and Low Cost Lithium-Sulfur Transportation Battery

“…Recently Kim et al demonstrated a Li-S cell with an electrode loading of 9 mAh/cm 2 , evidencing that engineered sulfur cathodes could achieve and preserve the required high areal capacities by tailoring both the anode and the cathode. 23 We conclude that the limiting factor in achieving the Li-S cathode targets is the need to identify electrolyte systems and strategies that enable starved electrolyte based electrodes that also achieve good cyclability and rate capability.…”

“…8 A variety of porous carbons, polymers, metal oxides and functionalized graphenes have been developed in an attempt to contain the soluble polysulfide intermediates through both physical and chemical interactions. [8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23] In addition to mitigating the polysulfide shuttle, engineered S cathodes have enhanced electronic conductivity and may accommodate the volume change in the cathode during cycling. [8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23] Other approaches have focused on designing new electrolytes with limited polysulfide solubility thereby suppressing the polysulfide shuttle leading to excellent coulombic efficiency and improved capacity retention.…”

Visualising the problems with balancing lithium–sulfur batteries by “mapping” internal resistance

“…That the resistance increases similarly rapidly for both cells is further evidence that electrolyte consumption is responsible for cell failure, with said consumption occurring faster if the negative electrode excess is lower, with an increasingly unfavourable morphology of the lithium electrode the likely cause. 19 Simple strategies which target improved morphology of lithium, for example heavier alkali metal additives, 20 may be particularly effective in this regard.…”

Application of Robust Design Methodology to Battery Packs for Electric Vehicles: Identification of Critical Technical Requirements for Modular Architecture

“…Reports show that areal capacities for anode materials that have high gravimetric capacities, e.g., double walled Si-nanotube is approximately seventeen times less than the areal capacity for a graphite anode (4.1 mAh/cm 2 ) [58]. It is equivalent to material loading of 0.1 mg/cm 2 .…”