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Rechargeable Calcium–Sulfur Batteries Enabled by an Efficient Borate‐Based Electrolyte
Author(s) -
Li Zhenyou,
Vinayan Bhaghavathi Parambath,
Diemant Thomas,
Behm Rolf Jürgen,
Fichtner Maximilian,
ZhaoKarger Zhirong
Publication year - 2020
Publication title -
small
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.785
H-Index - 236
eISSN - 1613-6829
pISSN - 1613-6810
DOI - 10.1002/smll.202001806
Subject(s) - electrolyte , anode , polysulfide , sulfur , electrochemistry , redox , battery (electricity) , inorganic chemistry , materials science , energy storage , sulfide , metal , calcium , boron , chemistry , chemical engineering , nanotechnology , electrode , metallurgy , organic chemistry , power (physics) , physics , quantum mechanics , engineering
Rechargeable metal–sulfur batteries show great promise for energy storage applications because of their potentially high energy and low cost. The multivalent‐metal based electrochemical system exhibits the particular advantage of the feasibility of dendrite‐free metal anode. Calcium (Ca) represents a promising anode material owing to the low reductive potential, high capacity, and abundant natural resources. However, calcium–sulfur (Ca–S) battery technology is in an early R&D stage, facing the fundamental challenge to develop a suitable electrolyte enabling reversible electrochemical Ca deposition, and at the same time, sulfur redox reactions in the system. Herein, a study of a room‐temperature Ca–S battery by employing a stable and efficient calcium tetrakis(hexafluoroisopropyloxy) borate Ca[B(hfip) 4 ] 2 electrolyte is presented. The Ca–S batteries exhibit a cell voltage of ≈ 2.1 V (close to its thermodynamic value) and good reversibility. The mechanistic studies hint at a redox chemistry of sulfur with polysulfide/sulfide species involved in the Ca‐based system.