Investigation of Lithium Polyacrylate Binders for Aqueous Processing of Ni‐Rich Lithium Layered Oxide Cathodes for Lithium‐Ion Batteries

Abstract

Ni-rich layered oxide cathodes are promising candidates to satisfy the increasing energy demand of lithium-ion batteries for automotive applications. Aqueous processing of such materials, although desirable to reduce costs and improve sustainability, remains challenging due to the Li + /H + exchange upon contact with water, resulting in a pH increase and corrosion of the aluminum current collector. Herein, an example was given for tuning the properties of aqueous LiNi 0.83 Co 0.12 Mn 0.05 O 2 electrode pastes using a lithium polyacrylate-based binder to find the "sweet spot" for processing parameters and electrochemical performance. Polyacrylic acid was partially neutralized to balance high initial capacity, good cycling stability, and the prevention of aluminum corrosion. Optimized LiOH/polyacrylic acid ratios in water were identified, showing comparable cycling performance to electrodes processed with polyvinylidene difluoride requiring toxic N-methyl-2pyrrolidone as solvent. This work gives an exemplary study for tuning aqueous electrode pastes properties aiming towards a more environmentally friendly processing of Ni-rich cathodes.

Limitations of Polyacrylic Acid Binders When Employed in Thick LNMO Li-ion Battery Electrodes

“…The use of PAA and/or its Li-or Na-salts as a binder for lithiumion battery electrodes has been investigated across various battery chemistries including silicon nanoparticle-based electrodes, 9 graphite, 42,43 LiFePO 4 , 44 LNMO, 45 Ni-rich layered oxide cathodes, 11 among others, highlighting the applicability of these materials as binders. It has an ability to create hydrogen bonds with the active material, and thereby limit the contact with the electrolyte.…”

“…Thereby, they act to some degree as an "artificial" interphase layer, as previously demonstrated for both positive and negative electrodes. [8][9][10][11][12][13][14] The overall performance of a battery can be significantly impacted by the performance of the binder, even though it is only present in small amounts. Firstly, the binder needs to strongly adhere to both the active material and the current collector to create a uniform and stable layer that can withstand any mechanical pressure during battery operation.…”

Influence of Phosphate Surface Coating on Performance of Aqueous‐Processed NMC811 Cathodes in 3 Ah Lithium‐Ion Cells

“…The electrochemical performance and stability of these materials are compromised due to issues like lithium and transition metal leaching and corrosion of the aluminum current collector. [13][14][15] To mitigate these problems, several strategies have been reported in literature. These strategies including the addition of acids, [16][17][18][19][20][21] the use of pressurized CO 2 , [22] adjusting the binder composition, [3,14,21,23] employing carbon-coated aluminum foil [24] and applying surface coatings.…”

A Smart Polymeric Sol‐Binder for Building Healthy Active‐Material Microenvironment in High‐Energy‐Density Electrodes

“…With the help of the significance of ME@AM and its strong ties to the binder system, we can comprehensively summarize the past efforts, the challenges, and future opportunities for the studies of binders. In general, the past efforts on binder research can be divided into three categories: improvement of adhesion or component binding capability, [18][19][20][21][22][23][24][25] functionalization for ion/electron conduction or volume change accommodation, [16,17,23,[26][27][28][29][30][31] and the rational design of binder systems for electrode processing innovation as well as microstructure management. [2,[32][33][34][35] Specifically, to improve the adhesion property that is critical for stabilizing the structures/interfaces of ME@AM, lots of efforts can be found on replacing poly(vinylidene fluoride) (PVDF) by other polymers with abundant polar functional groups (e.g., COOH, CN, OH, etc.).…”

“…[2,[32][33][34][35] Specifically, to improve the adhesion property that is critical for stabilizing the structures/interfaces of ME@AM, lots of efforts can be found on replacing poly(vinylidene fluoride) (PVDF) by other polymers with abundant polar functional groups (e.g., COOH, CN, OH, etc.). [18][19][20][21][22]24] In addition to rational design of chemical groups of binder chains, we recently proposed the strategies of binder modification based on chain adhesion physics, which showed that amorphous structure was beneficial to form strong and uniform binding among particles due to its high-level free energy. Therefore, we have employed polymer blends or alloys to improve the binding properties, and so the structural uniformity and stability of the ME@AM.…”