All Solid-State Lithium–Sulfur Battery Using a Glass-Type P₂S₅–Li₂S Electrolyte: Benefits on Anode Kinetics

Abstract

Lithium-sulfur (Li-S) batteries are promising candidates for next generation electrical energy storage devices due to their high specific energy. Despite intense research, there are still a number of technical challenges in developing a high performance Li-S battery. To elucidate the issues, an all solid-state Li-S battery was fabricated using Li 3 PS 4 solid electrolyte. Most of the theoretical capacity of sulfur, 1600 mAhg −1 was attained in the initial discharge-charge cycles with a high coulombic efficiency approaching 99%. To verify the benefit of the solid state electrolyte, galvanostatic stripping-deposition tests were also carried out on a symmetrical Li/Li cell and compared with those of a liquid electrolyte (1 M-lithium bis(trifluoromethane sulfonyl) imide (LiTFSI) in a mixture of 1,3-dioxolane (DOL)-diethoxyethane (DEE)). The kinetics and thermodynamics of the solid-state cell are discussed from the viewpoint of the charge transfer processes. This study demonstrates both the merits and drawbacks of using the solid sulfide electrolyte in a Li-S battery and facilitates the further improvement of this important high energy storage device. Lithium-sulfur (Li-S) batteries are attracting growing interest owing to their high specific energy above 3000 Whkg −1 (active material). However, before this technology can be used in practice, there are some significant challenges to overcome, including red-ox shuttle of polysulfides as well as poor lithium cycle performance.The polysulfide redox shuttle originates from the dissolution of the cathode material into the organic electrolyte. So far, various approaches have been suggested to solve the red-ox shuttle issue. LiNO 3 is a well-known additive for optimizing the solid electrolyte interphase (SEI) on lithium metal electrode, such as to block the deposition of polysulfides.1,2 An ionommer (e.g., Nafion) has also been proposed for preventing the polysulfide migration 3 and a buffer solution containing polysulfides can facilitate a good cycle ability as well. 4 The poor lithium cycle performance is due to the consumption of lithium metal during the charge-discharge process. It is well known that the lithium cycling response is primarily determined by the type of electrolyte to which it is in contact. 5,6 In the development of lithiummetal secondary batteries the Figure of Merit (FOM) is the parameter used to evaluate the lithium cycling ability. 5,6 Although lithium metal has a high specific capacity of 3862 mAhg −1 , its effective degree of utilization (i.e., the lithium loss relative to the amount of total input lithium metal) has to be taken into account. Generally, a valid parameter to determine the cycle ability of the lithium anode is the efficiency. For instance, it is difficult to achieve an efficiency higher than 99% for lithium cycling in a typical liquid electrolyte cell due to losses during its dissolution-deposition reaction. Therefore, the improvement of the FOM of a liquid electrolyte Li-S battery has been a major challenge to enhance the charge-disc...

The Electrochemical Characteristics and Applicability of an Amorphous Sulfide-Based Solid Ion Conductor for the Next-Generation Solid-State Lithium Secondary Batteries

“…Also, it is clear that no redox shuttle was observed. This result is consistent with our previous report on the all-solid-state Li-S cell (Yamada et al, 2015). Unfortunately, the cycle performance was lower than the expectation.…”

“…The ionic conductivity was 1.2 mS cm −1 at 25°C, and it is approximately 10 times than that of amorphous Li3PS4 SE (Yamada et al, 2015).…”

“…We have shown the possibility of a practical 2-Ah class all-solid LIB using a sulfide electrolyte (Ito et al, 2014). We also have investigated the anode kinetics using Li3PS4, i.e., Li2S:P2S5 = 75:25 (Yamada et al, 2015). Use of the solid-state electrolyte greatly facilitates the design of a highly save battery unlike the ones using flammable organic liquid solvents.…”

Modeling interfaces between solids: Application to Li battery materials

“…This agrees well with experimental results that show the formation of a similar layer at the Li/Li 3 PS 4 interface. 43 The disordered nature of the Li 3 PS 4 /Li interface evident in Fig. 7 increases the variance in possible interface configurations.…”

Theoretical study of lithium ionic conductors by electronic stress tensor density and electronic kinetic energy density

“…As a preliminary stage of our research, we have applied our method to the crystal structures of and . In particular, the latter serves as a prototype for sulfide solid electrolytes which have been intensively studied recently . In the course of this study, we have found a method to characterize ionic bonding by the electronic stress tensor density and kinetic energy density.…”