Do eco-friendly binders affect the electrochemical performance of MOF@CNT anodes in lithium-ion batteries?

Abstract

Today, with the advancement of technology, the environment is in danger more than ever. Given the increasing use of lithium-ion batteries (LIBs), it is essential to find more suitable binders to replace the traditional ones. Despite the desirable characteristics of electroactive materials, only small amounts of binders can effectively maintain the mechanical integrity of electrodes. Given the environmental and economic approaches, organic-based traditional binders must be substituted with a new generation of binders. This study aimed to replace sodium carboxymethyl cellulose (Na-CMC), a linear polymeric derivative of cellulose, with polyvinylidene fluoride (PVDF) as a binder. It is worth mentioning that CMC is water-soluble and eco-friendly and naturally abundant. This study also examined the effect of CMC and PVDF on cobalt-based metal–organic frameworks (MOFs), as anode materials, in terms of surface morphology and electrochemical performance. The results indicated that after 130 cycles, CMC had a stable behaviour while PVDF had a 73% capacity fade, which confirms the better performance of CMC. The electrochemical tests also proved that CMC has the potential to improve the cycle life and rate capability of cobalt-based MOFs. Finally, to obtain more details on MWCNT-CMC and MWCNT-PVDF interactions, quantum calculations were employed. The results confirmed that the interaction in MWCNT-CMC is stronger than that in MWCNT-PVDF.