Preparation of Water-Resistant Surface Coated High-Voltage LiNi0.5Mn1.5O4 Cathode and Its Cathode Performance to Apply a Water-Based Hybrid Polymer Binder to Li-Ion Batteries

Complementary Strategies Toward the Aqueous Processing of High‐Voltage LiNi0.5Mn1.5O4 Lithium‐Ion Cathodes

“…[15] For standard anode materials such as graphite, replacing PVdF by water-soluble binders( usually am ixture of carboxymethyl cellulose (CMC) and styrene-butadiene rubber (SBR)) is well established andl eads to as afe, economical, ande nvironmentally friendly process. [24,25] The resulting formation of LiOH upon contact with water does not only reduce the amount of electrochemically available lithiumb ut also deteriorates the electrode/electrolyte interface chemistry and, thus, ultimately lowers the overall reversible capacity and cycling stability. [21,22] Thirty years ago, Manthiram and Goodenough [23] described the leaching of lithium ions from layered transition metal oxidesu pon exposure to moisture-a phenomenon subsequently observed also with many other cathode materials, including LNMO.…”

“…[16][17][18][19][20] Aqueousp rocessing of oxidebased cathode materials, however,i ss ignificantly more complicated owing to the high sensitivity of lithium transition-metal oxidest oward water. [22,24,25] At least as important, however,i st he detrimental effect of the harsh pH increaseassociated with the hydroxide formation, leading to the stepwise corrosion of the aluminumc urrent collector substrate according to Equations (1) and (2): [26][27][28] [24,25] The resulting formation of LiOH upon contact with water does not only reduce the amount of electrochemically available lithiumb ut also deteriorates the electrode/electrolyte interface chemistry and, thus, ultimately lowers the overall reversible capacity and cycling stability.…”

“…[21,22] Thirty years ago, Manthiram and Goodenough [23] described the leaching of lithium ions from layered transition metal oxidesu pon exposure to moisture-a phenomenon subsequently observed also with many other cathode materials, including LNMO. [24,25] The resulting formation of LiOH upon contact with water does not only reduce the amount of electrochemically available lithiumb ut also deteriorates the electrode/electrolyte interface chemistry and, thus, ultimately lowers the overall reversible capacity and cycling stability. [22,24,25] At least as important, however,i st he detrimental effect of the harsh pH increaseassociated with the hydroxide formation, leading to the stepwise corrosion of the aluminumc urrent collector substrate according to Equations (1) and (2): [26][27][28]…”

Deriving Structure‐Performance Relations of Chemically Modified Chitosan Binders for Sustainable High‐Voltage LiNi0.5Mn1.5O4 Cathodes

“…The search for alternative binders, allowing for the implementation of water as a replacement of toxic N ‐methylpyrrolidone (NMP), which is required for the use of mutagenic and teratogenic polyvinylidene difluoride (PVdF) as binder, has stimulated the creativity and inventiveness of researchers worldwide. The new systems proposed include inter alia water/ethanol‐processable polymers (e. g., fluoroacrylic polymers, TRD 202a), fluorine‐free macromolecules (e. g., poly(acrylic acid), PAA and poly(vinyl acetate), PVA), as well as bio‐derived polymers (e. g., alginates and their derivatives like carboxymethyl cellulose, CMC) . Among these, chitosan, the deacetylated derivative of chitin, is the second‐most abundant natural polymer after cellulose.…”

Surface double coating of a LiNiaCobAl1−a−bO2(a> 0.85) cathode with TiOxand Li2CO3to apply a water-based hybrid polymer binder to Li-ion batteries

“…In recent years, water-soluble and aqueous polymer binders, i.e., water-based polymer binders, have become of great interest as alternatives to the poly(vinylidene diuoride) (PVdF) binder dissolved in N-methyl-2-pyrrolidone (NMP) for the cathodes of lithium ion batteries (LIBs) from the viewpoints of environmentally friendly electrode fabrication processes and reducing the cost of LIBs. [1][2][3][4][5][6][7][8][9][10][11][12][13] However, cathode materials such as LiNi 0.5 Mn 1.5 O 4 , 11 LiNi a Co b Al 1ÀaÀb O 2 (NCA) 12 and Li-rich solidsolution layered cathodes, 13 which are promising candidates as next generation positive-electrode active materials with high energy density for LIBs, are not stable in water-based slurry solutions because they contain a small amount of alkaline species such as LiOH as aresidue in their production process 14 and when they are dispersed in a water-based coating slurry, their surfaces are dissolved and its pH is increased, resulting in the corrosion of the Al foil current collectors and the falling off of active cathode materials from the current collector surfaces. 12 To prevent such a damage of cathode materials some ways have been proposed including the use of buffer agents to inhibit the increase in pH in the water-based slurry 15 and a stainless steel foil current collector 16 and the surface coating of cathode materials by carbon, 11 metal oxides 12 and Li 2 CO 3 .…”