Thickness-tunable polyimide nanoencapsulating layers and their influence on cell performance/thermal stability of high-voltage LiCoO2 cathode materials for lithium-ion batteries

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

“…[14,15] At present,t here are two main approaches to improve the interfacial stability between the LCO electrode and nonaqueous electrolytes at elevated cut-off charge voltages.F irst, the LCO surface can be coatedw ith various materials,s uch as metal oxides (e.g.,A l 2 O 3 ,M gO,Z nO,Z rO 2 ), [16][17][18][19][20][21][22][23] metal phosphates (e.g.,A lPO 4 ), [24][25][26] metal fluorides/oxyfluorides (e.g.,A lF 3 ,Z rO x F y ), [27,28] Li ionc onductors (e.g.,L i 2 CO 3 , lithium phosphorus oxynitride,L i 3 PO 4 , Li 1.3 Al 0.3 Ti 1.7 (PO 4 ) 3 ), [15,[29][30][31] and polymers (e.g.,p olyimide). [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 ...…”

“…At present, there are two main approaches to improve the interfacial stability between the LCO electrode and nonaqueous electrolytes at elevated cut‐off charge voltages. 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 .…”

An ion conductive polyimide encapsulation: New insight and significant performance enhancement of sodium based P2 layered cathodes

“…46,49 This is consistent with the previously reported that the polyamic acid shows C=O bond at around 1650 cm -1 and it shifts to ~ 1780 cm -1 after successful imidization process. 48,49,58 In addition, a sharp intense peak at 1319 cm -1 can be identified as the stretching vibration of the imide C-N group in PI film. 25 These results collectively confirm the successful imidization of polyamic acid and the formation of PI film on NNMC surface.…”

Research Progress in Improving the Cycling Stability of High-Voltage LiNi0.5Mn1.5O4 Cathode in Lithium-Ion Battery

“…The effects of surface modifications with PI [82, 120–123] were reported and showed improvements in the performances of LNMO cathodes, too. The high polarity and outstanding film forming capability of PAA, plus its strong affinity to transitional inorganic materials surfaces, might contribute to a facile formation of a nanometer thick, highly continuous, and ionic-conductive PI encapsulating layer on the surface of active materials [124]. Particularly, Kim et al [125] reported that the LNMO cathodes modified by PI coating presented excellent cycling stability with capacity retention of >90% after 60 galvanostatic cycles at 55 °C.…”