Inorganic Electrolyte Solutions and Gels for Rechargeable Lithium Batteries

Abstract

A class of inorganic oxychloride compounds have been evaluated for use as electrolytic solvents in rechargeable lithium batteries. Compared with S02-based electrolytes, these showed much improved safety while maintaining room temperature conductivities of 1 0 10-2 S/cm and electrochemical voltage windows of 4.5 -5.5 V vs. Lit/Li and supporting reversible lithium metal deposition/stripping. With the addition of 2 -5% polymer, the solutions acquire rubbery character with little loss of conductivity and no change in electrochemical stability. Preliminary charge/discharge tests with intercalation-type cathode as well as sulfur-based cathode showed that these inorganic electrolytes can operate with excellent reversibility. * Electrochemical Society Student Member. ** Electrochemical Society Active Member. Results and DiscussionCompared with the other inorganic electrolyte solvents such as S02C12, SOCI2, and POCI3, solvents I, II, and Ill are much less volatile (Table I), and CH3SO2CI is less sensitive to moisture. Although II and Ill are crystalline at room temperature, their binary solutions with LiAICI4 have freezing points far below room temperature. If the mole fraction of LiAICI4 is less than 0.5, then no crys-

RETRACTED ARTICLE: Polymer electrolytes: characteristics and peculiarities

“…Because of its high performance, scientific communities adopted its use in liquid electrolytes as well, and initial results with the carbonaceous anode materials were worth satisfying [22]. The commercialization of this new salt by 3M Corporation in the 1990s sparked significant hope that it may replace the poorly conducting LiTf, the hazardous LiClO 4 , the thermally unstable LiBF 4 and LiPF 6 , and the toxic LiAsF 6 in lithium battery applications [21,23,78,79]. LiIm proved to be safe, thermally stable, and highly conducting: It melts at 236°C without decomposition (a rarity among lithium salts) and does not decompose up to 360°C [80].…”

Lithium metal anodes for rechargeable batteries

“…74 The inorganic salts formed in SEI lms are mainly determined by the salts used in the electrolytes. 91,101 For example, LiF and Li x AsF x formed in SEI when LiAsF 6 was used as the salt; Li 2 O, LiCl, LiClO 3 , and LiClO 2 formed when LiClO 4 was used; LiF and Li x PF x formed when LiPF 6 was used. 74 While the imperfection (disordered structure) of the SEI layer endows it with ionic conductivity, 102 the resistance of the SEI layer continues to increase with its thickness and the reduction of solution species becomes more selective.…”

“…The repeated breakdown and reparation of the SEI lms lead to consumption of solution, and therefore low cycling efficiency and short cycle life. 101,103 The dendrite also can short the battery and cause a severe safety issue.…”

Protected lithium anode with porous Al2O3layer for lithium–sulfur battery

“…34,35 In addition, the solid electrolyte interface on the surface of a lithium anode is unstable due to the continual consumption of fresh lithium anode and electrolyte, leading to poor cycle performance and low coulombic efficiency. [36][37][38] Particularly, the most severe problem faced by the lithium anode in a lithium-sulfur battery is the side reaction between lithium anode and soluble lithium polysuldes and the deposition of insoluble suldes (Li 2 S/Li 2 S 2 ) on the lithium anode. 32 It is difficult for these insulating suldes to be utilized in subsequent cycles, resulting in the loss of active material and very fast capacity fading.…”