TY - CHAP

T1 - Differences in Electrochemical Behavior of Molybdenum Disulfide Electrode Materials in Alkyl Carbonate and Dioxolane/ Dimethoxyethane Electrolytes

AU - Волков, Алексей Игоревич

AU - Толстопятова, Елена Геннадьевна

AU - Кондратьев, Вениамин Владимирович

PY - 2022/11/14

Y1 - 2022/11/14

N2 - Layered two-dimensional materials, such as molybdenum disulfide (MoS2) have earned widespread attention in multiple research areas, including various energy storage devices, most prominently in lithium-ion СТЕНДОВЫЕ ДОКЛАДЫ 155 batteries and supercapacitors. The main advantage of MoS2 in energy storage applications is its high theoretical specific capacity (670 mA h g−1), owing to a series of reactions (1–3): MoS 2 + x•Li + + x•e − Li x MoS 2 (1) Li x MoS 2 + (4−x)•Li + + (4−x)•e − Mo + 2Li 2 S (2) S + 2Li+ + 2e− Li2S (3) As the conversion reaction (2) is irreversible, the process (3) – the same one as in lithium-sulfur batteries – is predominantly responsible for the charge storage in the device after a few initial cycles. Firstly, this makes molybdenum disulfide a suitable initial component of the cathodes in lithium-sulfur batteries after the transformation of the material into S/Li 2 S redox pair. The molybdenum metal nanoparticles synthesized in situ via (2) can serve as covalent binding agents, reducing polysulfide shuttling, which is a common problem within lithium-sulfur batteries. Secondly, the emergence of S Li 2 S as the main redox process means that 1,3-dioxolane/1,2-dimethoxyethane mixtures (DOL:DME), typical for lithium-sulfur batteries, might be more suitable electrolytes. In addition, the presence of nanosized sulfur could effectively alleviate sulfur volume expansion during charge/discharge. In this work, we study MoS 2 -based electrode materials in CR2032 cells with lithium anode and either typical ethylene carbonate/diethyl carbonate (EC:DEC) with 1 mol dm−3 LiPF 6 electrolyte or DOL:DME with 1 mol dm−3 LiTFSI and 0.2 mol dm−3 LiNO 3 . The electrochemical studies show that the cells cycled in (0.6–2.7) V range in DOL:DME electrolytes demonstrate the initial specific capacity values of up to 815 mA h g−1 at a current density of 100 mA g−1, and retain 69% of the initial capacity value after 100 GCD cycles. In contrast, the electrodes cycled in EC:DEC in (0.05–3.0) V range provided 847 mA h g−1 initially, yet retained only 23% of the initial capacity after 100 GCD cycles. This shows the indisputable benefit of DOL:DME electrolyte use with MoS 2 -based electrodes, which may be promising for further application of such electrodes in lithium-ion or lithium-sulfur batteries. The authors would like to thank the Centre for X-ray СТЕНДОВЫЕ ДОКЛАДЫ 156 Diffraction Studies, the Interdisciplinary Resource Centre for Nanotechnology, the Centre for Physical Methods of Surface Investigation of the Research Park of Saint Petersburg State University. The work was funded by RFBR (grant № 20-33-90143).

AB - Layered two-dimensional materials, such as molybdenum disulfide (MoS2) have earned widespread attention in multiple research areas, including various energy storage devices, most prominently in lithium-ion СТЕНДОВЫЕ ДОКЛАДЫ 155 batteries and supercapacitors. The main advantage of MoS2 in energy storage applications is its high theoretical specific capacity (670 mA h g−1), owing to a series of reactions (1–3): MoS 2 + x•Li + + x•e − Li x MoS 2 (1) Li x MoS 2 + (4−x)•Li + + (4−x)•e − Mo + 2Li 2 S (2) S + 2Li+ + 2e− Li2S (3) As the conversion reaction (2) is irreversible, the process (3) – the same one as in lithium-sulfur batteries – is predominantly responsible for the charge storage in the device after a few initial cycles. Firstly, this makes molybdenum disulfide a suitable initial component of the cathodes in lithium-sulfur batteries after the transformation of the material into S/Li 2 S redox pair. The molybdenum metal nanoparticles synthesized in situ via (2) can serve as covalent binding agents, reducing polysulfide shuttling, which is a common problem within lithium-sulfur batteries. Secondly, the emergence of S Li 2 S as the main redox process means that 1,3-dioxolane/1,2-dimethoxyethane mixtures (DOL:DME), typical for lithium-sulfur batteries, might be more suitable electrolytes. In addition, the presence of nanosized sulfur could effectively alleviate sulfur volume expansion during charge/discharge. In this work, we study MoS 2 -based electrode materials in CR2032 cells with lithium anode and either typical ethylene carbonate/diethyl carbonate (EC:DEC) with 1 mol dm−3 LiPF 6 electrolyte or DOL:DME with 1 mol dm−3 LiTFSI and 0.2 mol dm−3 LiNO 3 . The electrochemical studies show that the cells cycled in (0.6–2.7) V range in DOL:DME electrolytes demonstrate the initial specific capacity values of up to 815 mA h g−1 at a current density of 100 mA g−1, and retain 69% of the initial capacity value after 100 GCD cycles. In contrast, the electrodes cycled in EC:DEC in (0.05–3.0) V range provided 847 mA h g−1 initially, yet retained only 23% of the initial capacity after 100 GCD cycles. This shows the indisputable benefit of DOL:DME electrolyte use with MoS 2 -based electrodes, which may be promising for further application of such electrodes in lithium-ion or lithium-sulfur batteries. The authors would like to thank the Centre for X-ray СТЕНДОВЫЕ ДОКЛАДЫ 156 Diffraction Studies, the Interdisciplinary Resource Centre for Nanotechnology, the Centre for Physical Methods of Surface Investigation of the Research Park of Saint Petersburg State University. The work was funded by RFBR (grant № 20-33-90143).

M3 - Conference abstracts

SP - 154

EP - 156

BT - Тезисы XVII международной конференции «Актуальные проблемы преобразования энергии в литиевых электрохимических системах»

Y2 - 14 November 2022 through 18 November 2022

ER -