Will lithium‐sulfur batteries be the next beyond‐lithium ion batteries and even much better?

Abstract

Lithium-ion batteries (LIBs) are undoubtedly the current working-horse in almost all portable electronic devices, electric vehicles, and even large-scale stationary energy storage. Given the problems faced by LIBs, a big question arises as to which battery(ies) would be the "Beyond LIBs" batteries. Among the front-runners, lithium-sulfur batteries (LSBs) have been extensively pursued owing to their intrinsically high energy density and extremely low cost.Despite the steady and sometimes exciting progress reported on sulfur chemistry and cell performance at laboratory scales over the past decade, one of the major bottlenecks is the poor cyclability. In this perspective, we examine the key challenges and opportunities faced by LSBs, as well as approaches at the materials, electrode/electrolyte and cell integration levels that can be taken to transform LSBs from a front-runner to a real leading champion in the pursuit of the "Beyond LIBs". While the key new mechanistic insights are very important, we propose a set of the near-future research directions for both the liquid and solid state LSBs, where the currently on-going parallel pursuits of both liquid and solid LSBs will be converging. The "liquid current" will gradually be taken over by "solid future" in the expected LSBs commercialization in the coming decade.

Insights into the Pseudocapacitive Behavior of Sulfurized Polymer Electrodes for Li–S Batteries

“…SP-2 (60 wt% S) and SP-3 (70 wt% S) show strong 435 and 470 cm −1 features with the peak area ratio A 435 /A 475 >2 indicating long chain S. In PPS, the sharp peak observed ≈475 cm −1 was previously assigned to 𝜑 − S deformation and out-of-plane vibrations. [3] A similar peak was found in SP-1N. By combining TGA and Raman spectroscopic data, it is seen that no S 8 is present in SP samples although long chain S x (x < 8) are predominant in SP-2 and SP-3.…”

“…Lithium-sulfur batteries (LSBs) have the potential for >400 miles driving range with practical capacities up to 500 Wh kg −1 (twice that of Li-ion batteries or LIBs) at the pack level. [1][2][3] In conventional LSBs, the cathode consists of insulating sulfur embedded into a conducting host, while a thin Li metal strip serves as the anode with a highly reversible reaction (S 8 + 16 Li ↔ 8 Li 2 S), resulting in ≈2.15 V versus Li/Li + . The high specific capacity of sulfur (1675 mAh g −1 ) gives a theoretical energy density of DOI: 10.1002/advs.202206901 2500 Wh kg −1 for an LSB cell, an order of magnitude higher than that of LIBs.…”

Li2S-Based Composite Cathode with in Situ-Generated Li3PS4 Electrolyte on Li2S for Advanced All-Solid-State Lithium–Sulfur Batteries

“…With a high theoretical specific capacity of 1166 mAh g –1 and a high melting point of 938 °C, Li 2 S is one of the raw materials for the synthesis of thiophosphate solid electrolytes. − This allows for the design of cathode structures with improved characteristics as various synthetic methods can be employed. However, the low ionic and electronic conductivities of Li 2 S are a major challenge and require the addition of electrolyte and conductive carbon additives during the preparation process, leading to a reduced active material content and limiting the ability to increase the active-material loading. − These limitations negatively impact the energy density of the batteries and raise doubts on the potential of all-solid-state batteries to fulfill the need for high-density energy storage applications. , …”

“…22−25 These limitations negatively impact the energy density of the batteries and raise doubts on the potential of all-solid-state batteries to fulfill the need for high-density energy storage applications. 26,27 Researchers have made significant efforts to enhance the performance of lithium sulfide-based all-solid-state lithium− sulfur batteries. 28−31 The main strategies employed include the preparation of nanoscale lithium sulfide materials to reduce the diffusion distance of lithium ions, 32−34 the use of carbon or electrolyte coatings to enhance material conductivity, 20,35−40 and the simultaneous synthesis of composites containing Li 2 S, carbon, and electrolytes to improve the three-phase interface contact.…”

ZIF-67 on Sulfur-Functionalized Graphene Oxide for Lithium–Sulfur Batteries

“…2600 Wh/kg) than the current commercial lithium-ion batteries (372 mA h g −1 , 200 Wh/kg). 1,2 However, the fast capacity fading and low sulfide utilization caused by the poor conductivity, complicated redox of sulfur, 3 and the shuttling of soluble lithium polysulfide (LiPSs, Li 2 S x , 4 ≤ x ≤ 8) hinder their practical applications. 4 Many efforts have been devoted to address these undesired issues by physical/chemical confinement and electrocatalysis of Li 2 S x (4 ≤ x ≤ 8), 5−16 such as carbon materials, 5−7 polymers, 8,9 metal compounds (oxides, 10 sulfides, 11 nitrides, 12 and carbides 13 ), and metal−organic frameworks (MOFs).…”