# Insight into the Mechanism of MXene Electrodes in Alkali Metal Batteries

## TL;DR

This paper explores how different alkali metal ions interact with MXene electrodes in batteries, revealing how ion size affects performance and stability.

## Contribution

The study provides a direct comparison of MXene electrode mechanisms with Li+, Na+, and K+ ions under identical conditions.

## Key findings

- Li+ shows intercalation plateau, Na+ intermediate behavior, and K+ surface-dominated adsorption.
- Larger ionic radius correlates with lower electrochemical reversibility and capacity retention over 300 cycles.
- MXene surface chemistry and vibrational modes change with delamination and cycling.

## Abstract

The future growth of alkali metal-based batteries requires an understanding of how ion size affects the exchange mechanisms. In this work, we present a direct, comparative electrochemical study of MXene-based electrodes mechanism vs. lithium (Li+), sodium (Na+), and potassium (K+) ions using the same electrochemical conditions. This controlled method enables an extensive investigation of the size-dependent interactions between the MXene structure and alkali metal ions. X-ray photoelectron spectroscopy and Raman analysis of TMAOH-treated Ti3C2Tx MXene electrodes show that delamination and cycling alter vibrational modes and the surface chemistry. Voltage profile study reveals diverse storage behaviors: Li+ has a prominent intercalation plateau, Na+ shows intermediate properties, and K+ displays sloping profiles, indicating surface-dominated adsorption. The significant correlation between ionic radius and electrochemical reversibility is shown by long-term cycling data over 300 cycles, which show greater capacity retention and stability for Li+ and progressively lower performance for Na+ and K+. These findings provide new mechanistic insights into MXene–ion interactions and build the foundation for developing MXene-based materials for specific alkali-ion chemistries in next-generation energy storage devices.