A review of rechargeable batteries for portable electronic devices

Lithium-sulfur (Li-S) batteries have arousing interest because of their high theoretical energy density. However, they often suffer from sluggish conversion of lithium polysulfides (LiPS) during the charge/discharge process. Single nickel (Ni) atoms on nitrogen-doped graphene (Ni@NG) with Ni-N4 structure are prepared and introduced to modify the separators of Li-S batteries. The oxidized Ni sites of the Ni-N4 structure act as polysulfide traps, efficiently accommodating polysulfide ion electrons by forming strong Sx 2- ⋅⋅⋅NiN bonding. Additionally, charge transfer between the LiPS and oxidized Ni sites endows the LiPS on Ni@NG with low free energy and decomposition energy barrier in an electrochemical process, accelerating the kinetic conversion of LiPS during the charge/discharge process. Furthermore, the large binding energy of LiPS on Ni@NG also shows its ability to immobilize the LiPS and further suppresses the undesirable shuttle effect. Therefore, a Li-S battery based on a Ni@NG modified separator exhibits excellent rate performance and stable cycling life with only 0.06% capacity decay per cycle. It affords fresh insights for developing single-atom catalysts to accelerate the kinetic conversion of LiPS for highly stable Li-S batteries.

Single Nickel Atoms on Nitrogen-Doped Graphene Enabling Enhanced Kinetics of Lithium-Sulfur Batteries.

The development of energy-storage devices has received increasing attention as a transformative technology to realize a low-carbon economy and sustainable energy supply. Lithium-sulfur (Li-S) batteries are considered to be one of the most promising next-generation energy-storage devices due to their ultrahigh energy density. Despite the extraordinary progress in the last few years, the actual energy density of Li-S batteries is still far from satisfactory to meet the demand for practical applications. Considering the sulfur electrochemistry is highly dependent on solid-liquid-solid multi-phase conversion, the electrolyte amount plays a primary role in the practical performances of Li-S cells. Therefore, a lean electrolyte volume with low electrolyte/sulfur ratio is essential for practical Li-S batteries, yet under these conditions it is highly challenging to achieve acceptable electrochemical performances regarding sulfur kinetics, discharge capacity, Coulombic efficiency, and cycling stability especially for high-sulfur-loading cathodes. In this Review, the impact of the electrolyte/sulfur ratio on the actual energy density and the economic cost of Li-S batteries is addressed. Challenges and recent progress are presented in terms of the sulfur electrochemical processes: the dissolution-precipitation conversion and the solid-solid multi-phasic transition. Finally, prospects of future lean-electrolyte Li-S battery design and engineering are discussed.

Lithium-Sulfur Batteries under Lean Electrolyte Conditions: Challenges and Opportunities.

Lithium-sulfur batteries are a major focus of academic and industrial energy-storage research due to their high theoretical energy density and the use of low-cost materials. The high energy density results from the conversion mechanism that lithium-sulfur cells utilize. The sulfur cathode, being naturally abundant and environmentally friendly, makes lithium-sulfur batteries a potential next-generation energy-storage technology. The current state of the research indicates that lithium-sulfur cells are now at the point of transitioning from laboratory-scale devices to a more practical energy-storage application. Based on similar electrochemical conversion reactions, the low-cost sulfur cathode can be coupled with a wide range of metallic anodes, such as sodium, potassium, magnesium, calcium, and aluminum. These new "metal-sulfur" systems exhibit great potential in either lowering the production cost or producing high energy density. Inspired by the rapid development of lithium-sulfur batteries and the prospect of metal-sulfur cells, here, over 450 research articles are summarized to analyze the research progress and explore the electrochemical characteristics, cell-assembly parameters, cell-testing conditions, and materials design. In addition to highlighting the current research progress, the possible future areas of research which are needed to bring conversion-type lithium-sulfur and other metal-sulfur batteries into the market are also discussed.

Current Status and Future Prospects of Metal–Sulfur Batteries

A review on the status and challenges of electrocatalysts in lithium-sulfur batteries

Designing Safe Electrolyte Systems for a High-Stability Lithium–Sulfur Battery

The development of membranes that block solutes while allowing rapid water transport is of great importance. The microstructure of the membrane needs to be rationally designed at the molecular level to achieve precise molecular sieving and high water flux simultaneously. We report the design and fabrication of ultrathin, ordered conjugated-polymer-framework (CPF) films with thicknesses down to 1 nm via chemical vapour deposition and their performance as separation membranes. Our CPF membranes inherently have regular rhombic sub-nanometre (10.3 × 3.7 Å) channels, unlike membranes made of carbon nanotubes or graphene, whose separation performance depends on the alignment or stacking of materials. The optimized membrane exhibited a high water/NaCl selectivity of ∼6,900 and water permeance of ∼112 mol m-2 h-1 bar-1, and salt rejection >99.5% in high-salinity mixed-ion separations driven by osmotic pressure. Molecular dynamics simulations revealed that water molecules quickly and collectively pass through the membrane by forming a continuous three-dimensional network within the hydrophobic channels. The advent of ordered CPF provides a route towards developing carbon-based membranes for precise molecular separation. 

https://repository.kaust.edu.sa/bitstream/10754/680191/1/Fast%20water%20transport%20submitted%20manuscript.pdf

Fast water transport and molecular sieving through ultrathin ordered conjugated-polymer-framework membranes

With the advent of the Internet of Things and big data, massive data must be rapidly processed and stored within a short timeframe. This imposes stringent requirements on memory hardware implementation in terms of operation speed, energy consumption, and integration density. To fulfill these demands, 2D materials, which are excellent electronic building blocks, provide numerous possibilities for developing advanced memory device arrays with high performance, smart computing architectures, and desirable downscaling. Over the past few years, 2D‐material‐based memory‐device arrays with different working mechanisms, including defects, filaments, charges, ferroelectricity, and spins, have been increasingly developed. These arrays can be used to implement brain‐inspired computing or sensing with extraordinary performance, architectures, and functionalities. Here, recent research into integrated, state‐of‐the‐art memory devices made from 2D materials, as well as their implications for brain‐inspired computing are surveyed. The existing challenges at the array level are discussed, and the scope for future research is presented.

Integrated Memory Devices Based on 2D Materials

Electrical manipulation of exchange bias (EB) enables an additional degree of freedom in the design of innovative spintronic devices. However, the electrical switching of EB via spin–orbit torque (SOT) has not been achieved in magnetic tunnel junctions (MTJs), which are one of the building blocks in spintronic devices. Herein, based on the SOT in antiferromagnets (AFMs), perpendicular EB reversal across AFM IrMn and ferromagnetic (FM) [Co/Pt]2 multilayer is demonstrated both in extended and confined geometries. In particular, in three‐terminal perpendicular MTJ devices, the switching of the EB using the SOT is achieved. Both high and low resistances are observed at the zero magnetic field during EB switching. The findings provide the direction to include a new functionality in spintronic devices and will inspire future research in exploring the electrical control of EB in SOT magnetic random access memory (SOT‐MRAM).

Electrical Manipulation of Exchange Bias in an Antiferromagnet/Ferromagnet‐Based Device via Spin–Orbit Torque

Insulating compensated ferrimagnets, especially hosting room-temperature compensation points, are considered promising candidates for developing ultra-high-density and ultrafast magnonic devices owing to combining the characteristics of both ferromagnets and antiferromagnets. These intriguing features become outstanding close to their compensation points. However, their spin-orbit torque (SOT)-induced magnetization switching, particularly in the vicinity of the compensation points, remains unclear. Herein, we systematically investigated the SOT in insulating compensated ferrimagnetic Gd3Fe5O12/Pt heterostructures with perpendicular magnetic anisotropy. A nearly room-temperature compensation point (Tcomp ∼ 297 K) was consistently identified by the magnetization curves, spin Hall-induced anomalous Hall effect, and spin Hall magnetoresistance measurements. Moreover, using 100 ns duration pulsed current, deterministic current-induced magnetization switching below and above Tcomp, even at 294 and 301 K, was achieved with opposite switching polarity. It is found that a large current is required to switch the magnetization in the vicinity of Tcomp, although the effective SOT field increases close to Tcomp. Our finding provides alternative opportunities for exploring ultrafast room-temperature magnon-based devices.

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Yinchang Ma

Papers

Designing Safe Electrolyte Systems for a High-Stability Lithium–Sulfur Battery

Fast water transport and molecular sieving through ultrathin ordered conjugated-polymer-framework membranes

Integrated Memory Devices Based on 2D Materials

Electrical Manipulation of Exchange Bias in an Antiferromagnet/Ferromagnet‐Based Device via Spin–Orbit Torque

Current-Induced Magnetization Switching Across a Nearly Room-Temperature Compensation Point in an Insulating Compensated Ferrimagnet.