Structured aqueous processed lignin-based NMC cathodes for energy-dense LIBs with improved rate capability

Abstract

The cost and environmental impact of Li-ion batteries can be reduced through aqueous processing of cathode materials. Here, we used aqueous processing to prepare lignin-based NMC111 cathodes for Li-ion batteries with enhanced rate capability.

Bio-Based Binder Development for Lithium-Ion Batteries

“…The development of bio-based binders for the positive electrode, i.e., the cathode, in LIBs is more scarcely reported than for graphite- and Si-based anodes. The binder requirements and performance are more complex due to various applied cathode chemistries, such as LiFePO 4 (LFP), LiMnO 2 (LMO), and Li(Ni x Mn y Co z )O 2 for (x + y + z = 1) (NMC) [ 2 , 87 ]. Moreover, certain cathode materials, especially NMC and LMO, are highly sensitive to humid air and water, and their exposure can result in the formation of lithium carbonates and lithium hydroxide, which can affect the cyclic performance [ 91 ].…”

“…Moreover, certain cathode materials, especially NMC and LMO, are highly sensitive to humid air and water, and their exposure can result in the formation of lithium carbonates and lithium hydroxide, which can affect the cyclic performance [ 91 ]. Several bio-based binder systems have been identified and investigated, such as lignin [ 47 , 87 , 88 ], sodium alginate [ 48 , 86 ], cellulose-based [ 89 , 90 , 92 , 93 ], tragacanth gum [ 43 ], and others [ 94 ]. It was shown that the modification of the pH in an LFP–CMC-based aqueous slurry can significantly reduce the oxidation of Fe(II) and the formation of Li 3 PO 4 on the electrode’s surface [ 95 , 96 ].…”

“…The use of the lignin binder in the LiFePO 4 cathode has demonstrated a reversible capacity of 148 mAh g −1 at 0.1 C and 117 mAh g −1 at a rate of 1 C [ 47 ]. The introduction of a lignin-based binder to the NMC111 cathode has demonstrated similar performance to the PVDF binder and a specific capacity of about 140 mAh g −1 at 0.1 C [ 87 ]. The increase of the C rate led to a significant decrease in the specific capacity for the lignin-based binder system [ 87 ].…”

“…The introduction of a lignin-based binder to the NMC111 cathode has demonstrated similar performance to the PVDF binder and a specific capacity of about 140 mAh g −1 at 0.1 C [ 87 ]. The increase of the C rate led to a significant decrease in the specific capacity for the lignin-based binder system [ 87 ]. A more-stable performance was found with the CMC/lignin binder in the NMC111 cathode system at increasing C rates [ 88 ].…”

Versatile Composite Binder with Fast Lithium-Ion Transport for LiCoO2 Cathodes

“…A binder is a significant contributor to the evolution of the electrode structure. The development of new binders with different functions has gradually become a key to solve the low ion transport performance. − Building the efficient ion transport channels inside the electrodes and realizing the high-speed transport is one of the key research directions for future battery technologies. − More specifically, the binder determines the microscopic and interfacial evolution during electrode fabrication through its own physical and chemical properties. − Poly­(vinylidene fluoride) (PVDF) is a commonly used binder in LIBs owing to its electrochemical stability. However, the low ionic conductivity of PVDF results in a slow Li + diffusion rate, − which, in turn, affects the reaction kinetics and further restricts the application of high-rate LIBs. − Therefore, new binders with good adhesion properties and high-rate properties are significant for the manufacture of high-power LIBs.…”