Stabilizing zinc anode via a chelation and desolvation electrolyte additive

The uncontrollable dendrites growth and intricately water-induced side reactions occurred on zinc anode leads to safety issues and poor electrochemical kinetics,which largely limit the widespread application of zinc-ion batteries(ZIBs).Herein,ethylenediaminetetraacetic acid disodium salt(EDTA-2Na)is utilized as an electrolyte additive to strengthen the reversibility and cycling stability of zinc anode.Experimental results and theoretical calculation demonstrate that the EDTA-2Na presents a much stronger coordination with Zn^(2+)when comparing with H_(2)O molecular,implying the EDTA-2Na is capable to enter the solvation shell of[Zn(OH_(2))_(6)]^(2+)and coordinate with Zn^(2+)ions,thus achieving a flat and smooth zinc deposition with less by-products(Zn_(4)SO_(4)(OH)6·xH_(2)O and H_(2)).Consequently,the zinc symmetric battery with EDTA-2Na additive delivers an excellent cycling stability up to 1800 h under current density of 1 mA cm^(-2),and the hydrogen evolution reaction(HER),corrosion,by-product issues are significantly inhibited.Moreover,the rate performance and stability of coin-type and pouch-type Zn||MnO2/graphite batteries are significantly boosted via EDTA-2Na additive(248 mAh g^(-1)at 0.1 A g^(-1),81.3%after 1000 cycles at a A g^(-1)).This kind of electrolyte additive with chelation and desolvation functions shed lights on strategies of improving zinc anode stability for further application of ZIBs.

A double transition metal Ti_(2)NbC_(2)T_(x) MXene for enhanced lithium-ion storage

MXene,an emerging two-dimensional(2D)layered material,has received worldwide attention in various energy storage systems because of its excellent properties.Nevertheless,the low capacity of pristine MXene restricts its application in energy storage devices especially for the lithium-ion batteries(LIBs).To address the above issue,herein,a stable and highly conductive double transition metal MXene(Ti_(2)NbC_(2)T_(x)) is successfully fabricated,which provides enlarged interlayer spacing and excellent conductivity for fast ion diffusion and charge transfer.Taking the Ti_(2)NbC_(2)T_(x)s anode for LIBs,a superior specific capacity of 196.2 mAh·g-1and an excellent long-term cycling stability of~100%after 400cycles under 0.1 A·g^(-1) are achieved for LIBs.In particular,Ti_(2)NbC_(2)T_(x) delivers an impressive capacity retention of 81%over 4000 cycle under 1 A·g^(-1),outperforming the Ti_(3)C_(2)T_(x) and various previously reported MXene-based materials.Our results offer an attractive strategy for the future application of MXene-based materials.