Ultralong-Lifespan Magnesium Batteries Enabled by the Synergetic Manipulation of Oxygen Vacancies and Electronic Conduction

Abstract

As a potential next-generation energy storage system, rechargeable magnesium batteries (RMBs) have been receiving increasing attention due to their excellent safety performance and high energy density. However, the sluggish kinetics of Mg2+ in the cathode has become one of the main bottlenecks restricting the development of RMBs. Here, we introduce oxygen vacancies to spherical NaV6O15 cross-linked with carbon nanotubes (CNTs) (denoted as SNVO X -CNT) as a cathode material to achieve an impressive long-term cycle life of RMBs. The introduction of oxygen vacancies can improve the electrochemical performance of the NaV6O15–X cathode material. Besides, owing to the introduction of CNTs, excellent internal/external electronic conduction paths can be built inside the whole electrode, which further achieves excellent electrochemical performance. Moreover, such a unique structure can efficiently improve the diffusion kinetics of Mg2+ (ranging from 1.28 × 10–12 to 7.21 × 10–12 cm2·s–1). Simulation calculations further prove that oxygen vacancies can cause Mg2+ to be inserted in NaV6O15–X . Our work proposes a strategy for the synergistic effect of oxygen vacancies and CNTs to improve the diffusion coefficient of Mg2+ in NaV6O15 and enhance the electrochemical performance of RMBs.

Engineering oxygen vacancies in Na2Ti3O7 for boosting its catalytic performance in MgH2 hydrogen storage

“…As evidently demonstrated in the literature, defect engineering is an effective strategy to expose more active sites and tune the structural regularity and band structure of nanostructured catalysts 26,27 29 . However, the correlation between defects and catalyst activity, and the mechanism of the defects in hydrogen storage are still not well understood 30,31,32 .…”

Engineering the Oxygen Vacancies in Na2Ti3O7 for Boosting Its Catalytic Performance in MgH2 Hydrogen Storage

“…As evidently demonstrated in the literature, defect engineering is an effective strategy to expose more active sites and tune the structural regularity and band structure of nanostructured catalysts 26,27 . The defect could function as active sites for the capture of H 2 molecules and the diffusion of H atoms, which would facilitate MgH 2 activation and result in high catalytic performance in hydrogen storage 28 .…”

Modification of a Cu Mesh with Nanowires and Magnesiophilic Ag Sites to Induce Uniform Magnesium Deposition

“…After Aurbach et al developed the first prototype of RMBs over two decades ago, mainstream research has focused on the design of cathode materials for the rapid diffusion dynamics of Mg 2+ ions as well as electrolytes for compatibility with electrodes and accomplished considerable advances. − Until recently, several original and unconventional studies were reported, which have intrigued researchers and inspired them to further scrutinize RMBs, such as engineering an artificial solid–electrolyte interface (SEI) on Mg metal, − exploring the interface evolution process between Mg metal and noncorrosive electrolytes, and regulating Mg electrodeposition behaviors. − The expected high safety, which is a significant incentive of Mg batteries, is also challenged by some novel studies.…”