Functional Electrolytes: Recent Advances in Development of Additives for Resistance Reduction

Abstract

The concept of "Functional Electrolytes" first reported in 1999 by Ube Industries, Ltd. provides improved battery performances by adding miniscule amounts of various additives to highly purified base-electrolytes, which deliberately induce additive decomposition to form "Controlled Thin Layer (CTL)" instead of uncontrolled formation of undesired thick SEI. Recently we examined various sulfonate esters and evaluated the influence of substituent groups on the battery resistance. The resistance reduction effect is found to be greater for highly branched structures or highly distortional structures of sulfonate esters. Interestingly, even Li salts containing a sulfonate ester structure shows a strong resistance reduction effect. Impedance measurements of the cathode and the anode reveal that additives suppress the cathode resistance increase by electrochemical process rather than chemical process.

Three‐Component Functional Additive in a LiPF6‐Based Carbonate Electrolyte for a High‐Voltage LiCoO2/Graphite Battery System

“…[32] However, it is generally accepted that functional electrolyte additives are of considerable importance in modifying and stabilizing the solid-electrolyte interface( SEI) layer, which determines the cycle life and safety of LIBs significantly. [8][9][10][33][34][35][36][37][38][39] Hence, the second strategy is the development of new electrolytesf or LCO-based cells using functional additives,s uch as phenyl-containing compounds (e.g.,b enzenes, [40][41][42][43] anilines, [43,44] phenyl-containing ether or thioethers [41,43,45] ), heterocyclic compounds (e.g.,t hiophenes, [41-43, 46, 47] furans, [41,43] pyrroles, [41] bismaleimide monomers, [48,49] sulfonates, [50] cyclic carbonates [14] ), phosphazenes, [51] boron-based anion receptors, [52] aliphatic dinitriles, [53] and inorganic materials (e.g.,A l 2 O 3 ,L i 2 CO 3 ). [54,55] Actually,m ost of these functionala dditives are effective to protectt he LCO cathode by participating in the modification of the SEI layer (sometimes forming ac onductivep olymeric film) to stabilize the electrode-electrolyte interfacee fficiently by suppressing undesired parasitic reactions.…”

“…First, the LCO surface can be coated with various materials, such as metal oxides (e.g., Al 2 O 3 , MgO, ZnO, ZrO 2 ), metal phosphates (e.g., AlPO 4 ), metal fluorides/oxyfluorides (e.g., AlF 3 , ZrO x F y ), Li ion conductors (e.g., Li 2 CO 3 , lithium phosphorus oxynitride, Li 3 PO 4 , Li 1.3 Al 0.3 Ti 1.7 (PO 4 ) 3 ), and polymers (e.g., polyimide) . However, it is generally accepted that functional electrolyte additives are of considerable importance in modifying and stabilizing the solid–electrolyte interface (SEI) layer, which determines the cycle life and safety of LIBs significantly . Hence, the second strategy is the development of new electrolytes for LCO‐based cells using functional additives, such as phenyl‐containing compounds (e.g., benzenes, anilines, phenyl‐containing ether or thioethers), heterocyclic compounds (e.g., thiophenes, furans, pyrroles, bismaleimide monomers, sulfonates, cyclic carbonates), phosphazenes, boron‐based anion receptors, aliphatic dinitriles, and inorganic materials (e.g., Al 2 O 3 , Li 2 CO 3 ) .…”

Sodium ion conducting NaI-Na<SUB align="right">3PO<SUB align="right">4 solid electrolyte with PLLTMEDA as an additive for solid state batteries

“…Some commonly used additives by researchers are vinylene carbonate [18], vinyl ethylene carbonate [19] and vinyl ethylene sulphite [20]. These additives which are also known as functional materials for functional electrolytes are reported to be fully utilised in developing battery design with improved electrochemical performance [21][22][23][24]. According to literature, zwitterionic polymer gave a great effect on ionic conductivity owing to structural modification during the preparation of the sample [25].…”

Investigation of the Storage Behavior of Shredded Lithium‐Ion Batteries from Electric Vehicles for Recycling Purposes

“…presented a carbene PF 5 adduct for overcharge protection . Furthermore, many other additives and further LIB electrolyte formulations for achieving improved performance and safety are possible …”

“…[10] Furthermore, many other additives and furtherL IB electrolyte formulations for achieving improved performance and safetya re possible. [4][5][6][7][11][12][13][14][15][16][17][18][19][20][21][22][23][24][25][26] LIBs loose capacity over time owing to different aging phenomena. [27] Various reports focusedo nm ethod development for aging investigationso fd ifferent cell components [28][29][30][31][32] and the electrolyte are availablei nt he literature.…”