Novel K2Ti8O17 Anode via Na+/Al3+ Co-Intercalation Mechanism for Rechargeable Aqueous Al-Ion Battery with Superior Rate Capability.

Qiangqiang Feng,Wei Feng,Jitong Yan,Shaozheng Ji,Yongfu Tang,Yanyan Liu

doi:10.3390/nano11092332

Abstract

A promising aqueous aluminum ion battery (AIB) was assembled using a novel layered K2Ti8O17 anode against an activated carbon coated on a Ti mesh cathode in an AlCl3-based aqueous electrolyte. The intercalation/deintercalation mechanism endowed the layered K2Ti8O17 as a promising anode for rechargeable aqueous AIBs. NaAc was introduced into the AlCl3 aqueous electrolyte to enhance the cycling stability of the assembled aqueous AIB. The as-designed AIB displayed a high discharge voltage near 1.6 V, and a discharge capacity of up to 189.6 mAh g−1. The assembled AIB lit up a commercial light-emitting diode (LED) lasting more than one hour. Inductively coupled plasma–optical emission spectroscopy (ICP-OES), high-resolution transmission electron microscopy (HRTEM), and X-ray absorption near-edge spectroscopy (XANES) were employed to investigate the intercalation/deintercalation mechanism of Na+/Al3+ ions in the aqueous AIB. The results indicated that the layered structure facilitated the intercalation/deintercalation of Na+/Al3+ ions, thus providing a high-rate performance of the K2Ti8O17 anode. The diffusion-controlled electrochemical characteristics and the reduction of Ti4+ species during the discharge process illustrated the intercalation/deintercalation mechanism of the K2Ti8O17 anode. This study provides not only insight into the charge–discharge mechanism of the K2Ti8O17 anode but also a novel strategy to design rechargeable aqueous AIBs.

Highlights

Rechargeable lithium-ion batteries as promising energy storage devices have been widely applied in portable electronic devices and electric vehicles [1,2]
As shown in the schematic (Figure 1a), the nanobelt K2 Ti8 O17 is formed on the surof the Ti foil via the facile hydrothermal reaction combined with a post-pyrolysis process
Face of the Ti foil via the facile hydrothermal reaction combined with a post-pyrolysis

Summary

Introduction

Rechargeable lithium-ion batteries as promising energy storage devices have been widely applied in portable electronic devices and electric vehicles [1,2]. Lithiumion batteries may be not the best choice for large-scale energy storage applications and practical power grids, concerning its uneven distribution and the long-term unavailability of lithium resources. ‘beyond-Li-ion’ batteries, including Mg-based batteries [3], Zn-based batteries [4,5], Na-based batteries [6], and Al-based batteries [7,8,9], have emerged as promising alternatives for electrochemical energy storage. The trivalent aluminum ion, in principle, provides three reactive electrons involved in the electrochemical processes ( Al 3+ + 3e− ↔ Al ), endowing a high volumetric capacity of 8040 mAh cm−3 and a gravimetric capacity of 2980 mAh g−1 [13].

Methods

Results

Conclusion