Effect of Carbon Nanotubes on the Na+ Intercalation Capacity of Binder Free Mn2V2O7-CNTs Electrode: A Structural Investigation

Abstract

Improvements in sodium intercalation in sodium cathodes have been debated in recent years. In the present work, we delineate the significant effect of the carbon nanotubes (CNTs) and their weight percent in the intercalation capacity of the binder-free manganese vanadium oxide (MVO)-CNTs composite electrodes. The performance modification of the electrode is discussed taking into account the cathode electrolyte interphase (CEI) layer under optimal performance. We observe an intermittent distribution of the chemical phases on the CEI, formed on these electrodes after several cycles. The bulk and superficial structure of pristine and Na+ cycled electrodes were identified via micro-Raman scattering and Scanning X-ray Photoelectron Microscopy. We show that the inhomogeneous CEI layer distribution strongly depends on the CNTs weight percentage ratio in an electrode nano-composite. The capacity fading of MVO-CNTs appears to be associated with the dissolution of the Mn2O3 phase, leading to electrode deterioration. This effect is particularly observed in electrodes with low weight percentage of the CNTs in which the tubular topology of the CNTs are distorted due to the MVO decoration. These results can deepen the understanding of the CNTs role on the intercalation mechanism and capacity of the electrode, where there are variations in the mass ratio of CNTs and the active material.

Low-Dimensional Structures for Smart Materials and Composites: Preparation, Properties and Applications

“…The authors illustrated some advantages of aerogels over traditional graphene-based materials, including the composition and tunable porous properties as solid extractants for UV-benzotriazoles. Parmar et al [12] investigated the CNT impact in the intercalation capacity of binder-free manganese vanadium oxide (MVO)-CNT composite electrodes for sodium-ion-batteries (SIBs). The authors analyzed the cathode-electrolyte-interphase (CEI) layer formed during cycling and observed variations in CEI distribution based on the CNT wt%.…”