scholarly journals Atomic-scale regulation of anionic and cationic migration in alkali metal batteries

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Pan Xiong ◽  
Fan Zhang ◽  
Xiuyun Zhang ◽  
Yifan Liu ◽  
Yunyan Wu ◽  
...  
Keyword(s):  
Alkali Metal ◽  
Electrostatic Interactions ◽  
High Performance ◽  
Metal Electrode ◽  
Atomic Scale ◽  
Ion Diffusion ◽  
Alkali Ions ◽  
Anions And Cations ◽  
Polypropylene Separator ◽  
Coated Separator

AbstractThe regulation of anions and cations at the atomic scale is of great significance in membrane-based separation technologies. Ionic transport regulation techniques could also play a crucial role in developing high-performance alkali metal batteries such as alkali metal-sulfur and alkali metal-selenium batteries, which suffer from the non-uniform transport of alkali metal ions (e.g., Li+ or Na+) and detrimental shuttling effect of polysulfide/polyselenide anions. These drawbacks could cause unfavourable growth of alkali metal depositions at the metal electrode and irreversible consumption of cathode active materials, leading to capacity decay and short cycling life. Herein, we propose the use of a polypropylene separator coated with negatively charged Ti0.87O2 nanosheets with Ti atomic vacancies to tackle these issues. In particular, we demonstrate that the electrostatic interactions between the negatively charged Ti0.87O2 nanosheets and polysulfide/polyselenide anions reduce the shuttling effect. Moreover, the Ti0.87O2-coated separator regulates the migration of alkali ions ensuring a homogeneous ion flux and the Ti vacancies, acting as sub-nanometric pores, promote fast alkali-ion diffusion.

scholarly journals Atomic-scale tandem regulation of anionic and cationic migration for long-life alkali metal batteries

2021 ◽  
Author(s):  
Pan Xiong ◽  
Fan Zhang ◽  
Xiuyun Zhang ◽  
Yifan Liu ◽  
Yunyan Wu ◽  
...  
Keyword(s):  
Alkali Metal ◽  
High Performance ◽  
Rechargeable Batteries ◽  
Atomic Scale ◽  
Fast Diffusion ◽  
Ion Diffusion ◽  
Fast Transport ◽  
Na Ions ◽  
Long Life ◽  
Severe Growth

Abstract Atomic-scale regulation of both cationic and anionic transport is of great significance in membrane-based separation technologies. Ionic transport regulation techniques could also play a crucial role in developing high-performance alkali metal batteries such as alkali metal-sulfur and alkali metal-selenium batteries, which suffer from the non-uniform transport of alkali metal ions and detrimental shuttling of polysulfide/polyselenide (PS) anions. These obstacles can cause severe growth of alkali metal dendrites and the irreversible consumption of active cathodes, leading to capacity decay and short cycling life. Herein, we report long-life alkali metal batteries enabled by atomic-scale tandem regulation of the migration of both alkali metal cations (Li+/Na+) and PS anions using negatively charged Ti0.87O2 nanosheets with Ti atomic vacancies. The shuttling of PS anions has been effectively eliminated via a robust electrostatic repulsion between the negatively charged nanosheets and PS anions. The negatively charged nanosheets can also regulate the migration of Li+/Na+ ions to ensure a homogeneous ion flux through efficient but light adhesion of Li+/Na+ ions within the nanosheets. The atomic Ti vacancies act as sub-nanometre pores to provide fast diffusion channels for Li+/Na+ ions. Therefore, eradication of PS shuttling and stable Li/Na-ion diffusion without compromising the fast transport of Li+/Na+ ions has been achieved for long-life alkali metal-sulfur and alkali metal-selenium batteries. This work provides a facile and effective strategy to regulate the transport of both cations and anions for developing advanced rechargeable batteries by using two-dimensional vacancy-enhanced materials.

scholarly journals Ab initio molecular dynamics and materials design for embedded phase-change memory

2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Liang Sun ◽  
Yu-Xing Zhou ◽  
Xu-Dong Wang ◽  
Yu-Han Chen ◽  
Volker L. Deringer ◽  
...  
Keyword(s):  
Phase Change ◽  
High Performance ◽  
Materials Design ◽  
Atomic Scale ◽  
Ab Initio Molecular Dynamics ◽  
Core Material ◽  
Structure Property ◽  
Switching Speed ◽  
Atomic Structures ◽  
Memory Applications

AbstractThe Ge2Sb2Te5 alloy has served as the core material in phase-change memories with high switching speed and persistent storage capability at room temperature. However widely used, this composition is not suitable for embedded memories—for example, for automotive applications, which require very high working temperatures above 300 °C. Ge–Sb–Te alloys with higher Ge content, most prominently Ge2Sb1Te2 (‘212’), have been studied as suitable alternatives, but their atomic structures and structure–property relationships have remained widely unexplored. Here, we report comprehensive first-principles simulations that give insight into those emerging materials, located on the compositional tie-line between Ge2Sb1Te2 and elemental Ge, allowing for a direct comparison with the established Ge2Sb2Te5 material. Electronic-structure computations and smooth overlap of atomic positions (SOAP) similarity analyses explain the role of excess Ge content in the amorphous phases. Together with energetic analyses, a compositional threshold is identified for the viability of a homogeneous amorphous phase (‘zero bit’), which is required for memory applications. Based on the acquired knowledge at the atomic scale, we provide a materials design strategy for high-performance embedded phase-change memories with balanced speed and stability, as well as potentially good cycling capability.

An alkali metal–selenium battery with a wide temperature range and low self-discharge

2019 ◽  
Vol 7 (38) ◽  
pp. 21774-21782 ◽  
Author(s):  
Xiaosen Zhao ◽  
Lichang Yin ◽  
Zhenzhen Yang ◽  
Gang Chen ◽  
Huijuan Yue ◽  
...  
Keyword(s):  
Synergistic Effect ◽  
Alkali Metal ◽  
Wide Temperature Range ◽  
High Performance ◽  
Temperature Range

A high performance alkali metal–selenium battery with a wide temperature range was obtained by the synergistic effect of microporous fixation and heteroatom adsorption.

Accelerating ion diffusion with unique three-dimensionally interconnected nanopores for self-membrane high-performance pseudocapacitors

Nanoscale ◽  
2017 ◽  
Vol 9 (46) ◽  
pp. 18311-18317 ◽  
Author(s):  
Yuan Gao ◽  
Yuanjing Lin ◽  
Zehua Peng ◽  
Qingfeng Zhou ◽  
Zhiyong Fan
Keyword(s):  
Aspect Ratio ◽  
Surface Area ◽  
Structural Stability ◽  
High Aspect Ratio ◽  
High Performance ◽  
Three Dimensional ◽  
Rate Capability ◽  
Large Surface Area ◽  
Nanoporous Structure ◽  
Ion Diffusion

Three-dimensional interconnected nanoporous structure (3-D INPOS) possesses high aspect ratio, large surface area, as well as good structural stability. Profiting from its unique interconnected architecture, the 3-D INPOS pseudocapacitor achieves a largely enhanced capacitance and rate capability.

Ultrahigh energy storage and ultrafast ion diffusion in borophene-based anodes for rechargeable metal ion batteries

2017 ◽  
Vol 5 (5) ◽  
pp. 2328-2338 ◽  
Author(s):  
Dewei Rao ◽  
Lingyan Zhang ◽  
Zhaoshun Meng ◽  
Xirui Zhang ◽  
Yunhui Wang ◽  
...  
Keyword(s):  
Energy Storage ◽  
Metal Ion ◽  
High Performance ◽  
Storage Systems ◽  
Ultrahigh Energy ◽  
Ion Diffusion ◽  
Energy Storage Systems ◽  
Increasing Demand

Since the turn of the new century, the increasing demand for high-performance energy storage systems has generated considerable interest in rechargeable ion batteries.

Multimodal Optical Nanoprobe for Advanced In-Situ Electron Microscopy

2012 ◽  
Vol 20 (6) ◽  
pp. 32-37 ◽  
Author(s):  
Y. Zhu ◽  
M. Milas ◽  
M.-G. Han ◽  
J.D. Rameau ◽  
M. Sfeir
Keyword(s):  
Electron Microscopy ◽  
Driving Forces ◽  
Atomic Scale ◽  
Magnetic Domains ◽  
Photovoltaic Devices ◽  
Electromagnetic Devices ◽  
In Situ Electron Microscopy ◽  
Electric And Magnetic Fields ◽  
Anions And Cations

In-situ electron microscopy has gained considerable attention in recent years. It provides a “live” view of a material or device under study at various length scales. For example, by heating or cooling a sample one can study structural change at the atomic scale to understand the driving forces and mechanisms of phase transitions. By applying electric and magnetic fields on a ferroelectric or magnetic architecture in operation, one can directly observe how electric and magnetic domains switch, how anions and cations shift their positions, and how spins change their configuration across a domain wall, aiding the development of better electromagnetic devices. In the study of photovoltaic devices and junctions, a major challenge is to directly correlate light-induced electric currents with local structural inhomogeneities and dynamics. Such a capability would allow us to evaluate the performance of individual p-n junctions and to improve optoelectronic efficiency.

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