Binders are one of the key components in a battery. They play a crucial role of interconnecting active materials & conducting carbon together with each other and with the current collector. State of the art binders like polyvinylidene fluoride (PVDF) necessitate the use of use of toxic and expensive solvents like n-methyl pyrrolidone (NMP). As an alternative several water processable binders like carboxymethyl cellulose (CMC), alginate etc. have been investigated. These binders do not have any intrinsic ionic conductivity and are not thermally stable. Taking this as a background, we revealed the potential of several ionically conducting phosphate and silicate based inorganic binders¹. These binders are not only ionically conducting, but also water processable, thermally stable (>1000°C), chemically compatible, eco- friendly and safe to use. These binders outperform standard PVDF and CMC based binders in their electrochemical performance in sodium-ion and solid-state batteries with different classes of electrode materials.  

In the follow up studies², we improved high rate capability of graphite anode with lithium based inorganic binders for lithium-ion batteries (LIB). SiOx surface coatings were carried out on graphite to improve adhesion with these binders, thus enabling high rate cyclic performance up to 20C stable for over 2000 cycles. High specific capacity of >315 mAhg-1 was achieved at 2C, stable for over 1000 cycles. The SiOx coatings were characterized by tip enhanced Raman spectroscopy and X-ray photoelectron spectroscopy. A total of six aqueous binders, three inorganic binders along with three well known reference binders are investigated for graphite for LIB.

References

[1] S. Trivedi; V. Pamidi; M. Fichtner; & A.R. Munnangi, Ionically conducting inorganic binders: a paradigm shift in electrochemical energy storage. Green Chemistry, 2022, 24, 5620–5631.

[2] S. Trivedi; S. Dhinda; Y. Tang; S. Fuchs; V. Pamidi; Helge Stein; A.R. Munnangi; M. Fichtner, SiOx coated Graphite with Inorganic Aqueous Binders as High-performance Anode for Lithium Ion Batteries. (under preparation).