Bifunctional Antioxidant for Concurrent Enhancement of Stability and Zinc-ion Storage Properties of Ti3C2Tx

Abstract

MXenes exhibit exceptional physicochemical properties, rendering them highly promising for applications in electrochemical energy storage devices. However, their easy oxidation and inherent tendency for self-stacking pose significant challenges, thereby limiting their utilization in practical application. In this study, sodium sulfide (Na2S) was used to enhance the stability of Ti3C2Tx under multiple environmental conditions. Additionally, compared to the reported antioxidation agents such as ascorbic acid (VC), sodium borohydride (NaBH4), sodium ascorbate (NaAc), and sodium bisulfite (NaHSO3), Na2S possesses an appropriate level of reducing strength, which was further used as the reducing agent to fabricate 3D macro-porous Ti3C2Tx/reduced graphene oxide (SMG) hydrogels at room temperature. This prevents the oxidation of Ti3C2Tx coming from the traditional heated gelation process and generates the porous structure conducive to the ion transport. As the free-standing cathode for zinc-ion storage, the SMG electrode possesses a high areal special capacity of 526.2 mF cm-2 at 2 mA cm-2, much higher than that of Ti3C2Tx/graphene oxide film (MG, 111.4 mF cm-2), together with outstanding cycle performance (83.2% capacity retention after 30000 cycles). This study presents Na2S as a bifunctional antioxidant for enhancing the stability of MXene and constructing 3D MXene-based aerogels at room temperature with exceptional zinc storage performance.