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Lithium-ion batteries (LIBs) are at the forefront of energy storage and highly demanded in consumer electronics due to their high energy density, long battery life, and great flexibility. However, LIBs usually suffer from obvious capacity reduction, security problems, and a sharp decline in cycle life under low temperatures, especially below 0 °C, which can be mainly ascribed to the decrease in Li+ diffusion coefficient in both electrodes and electrolyte, poor transfer kinetics on the interphase, high Li+ desolvation barrier in the electrolyte, and severe Li plating and dendrite. Targeting such issues, approaches to improve the kinetics and stability of cathodes are also dissected, followed by the evaluation of the application prospects and modifications between various anodes and the strategies of electrolyte design including cosolvent, blended Li salts, high-concentration electrolyte, and additive introduction. Such designs elucidate the successful exploration of low-temperature LIBs with high energy density and long lifespan. This review prospects the future paths of research for LIBs under cold environments, aiming to provide insightful guidance for the reasonable design of LIBs under low temperature, accelerating their widespread application and commercialization. [ABSTRACT FROM AUTHOR]

Lithium−sulfur batteries are one of the most promising energy storage systems due to their high energy density. Many efforts have been made to improve the electrochemical performance of lithium−sulfur batteries. However, the complex and time-consuming preparation process hinders their practical application. In this work, an ultra-fast and facile method has been proposed to prepare the sulfur/graphene composites in a simplified and time-saving preparation process with the assistance of microwave. Microwave is introduced to help sulfur fleetly deposit uniformly on the surface of graphene within just 30 s. Nano-sized sulfur within 30 nm is generated in this ultra-fast process. Lithium−sulfur batteries with as-prepared sulfur/graphene composites exhibit good cycling life with a capacity of 503.5 mAh g−1 at 0.2 C. This method makes it possible for lithium−sulfur batteries to be practical. [ABSTRACT FROM AUTHOR]

By virtue of its high specific surface area and low tortuosity for ionic storage and transportation, holey graphene has come to be regarded as a promising material for energy storage devices, such as lithium ion batteries, and supercapacitors. For practical applications, a scalable and green preparation method for holey graphene is required. This work proposes a facile preparation method for holey graphene by simply microwaving pristine graphene in air. Compared with previous scalable methods, this method exhibits much greater efficiency, reducing the preparation time from hours to minutes. The mechanism underlying the microwave irradiation-induced formation of nanosized holes involves the interaction between microwaves, electrons, oxygen in air, and carbon atoms in the defect areas of the graphene. The size, density, and distribution of holes can be controlled by tuning the microwave irradiation time and oxygen concentration. Used as a hybrid conductive agent, the as-prepared holey multilayer graphene increases capacitance retention to 96.25% at high current density (8 A g−1), and 96.48% in long cycles (1 A g−1 and 10 000 cycles). [ABSTRACT FROM AUTHOR]

Lithium-sulfur (Li-S) batteries are considered as next-generation technology for energy storage due to their high energy density. However, the rapid capacity fading resulted from the shuttle effect obstructs their practical application. Herein, ultrathin dense double-walled carbon nanotube (DWCNT) membrane has been designed to impede the shuttle effect. The outer wall of DWCNT helps to keep the integrity and conductivity for its inner wall. The defects on DWCNT are less than those on multi-walled CNT (MWCNT), which helps DWNCT to stack and form dense membrane. The tiny areal density of 0.00477 mg cm−2 of DWCNT membrane would not weaken the Li-S battery's energy density too much. The electrochemical tests suggested that the DWCNT membrane improved the cycling performance effectively. A possible reason was discussed. The cathode electrolyte interphase (CEI) grown on the DWCNTs made the membrane further dense, which promoted the blocking effect on polysulfides. [ABSTRACT FROM AUTHOR]

Sub-100 nm hollow carbon nanospheres with thin shells are highly desirable anode materials for energy storage applications. However, their synthesis remains a great challenge with conventional strategies. In this work, we demonstrate that hollow carbon nanospheres of unprecedentedly small sizes (down to ∼32.5 nm and with thickness of ∼3.9 nm) can be produced on a large scale by a templating process in a unique reverse micelle system. Reverse micelles enable a spatially confined Stöber process that produces uniform silica nanospheres with significantly reduced sizes compared with those from a conventional Stöber process, and a subsequent well-controlled sol-gel coating process with a resorcinol-formaldehyde resin on these silica nanospheres as a precursor of the hollow carbon nanospheres. Owing to the short diffusion length resulting from their hollow structure, as well as their small size and microporosity, these hollow carbon nanospheres show excellent capacity and cycling stability when used as anode materials for lithium/sodium-ion batteries. [ABSTRACT FROM AUTHOR]

Conventional bulky and rigid power systems are incapable of meeting flexibility and breathability requirements for wearable applications. Despite the tremendous efforts dedicated to developing various 1D energy storage devices with sufficient flexibility, challenges remain pertaining to fabrication scalability, cost, and efficiency. Here, a scalable, low-cost, and high-efficiency 3D printing technology is applied to fabricate a flexible all-fiber lithium-ion battery (LIB). Highly viscous polymer inks containing carbon nanotubes and either lithium iron phosphate (LFP) or lithium titanium oxide (LTO) are used to print LFP fiber cathodes and LTO fiber anodes, respectively. Both fiber electrodes demonstrate good flexibility and high electrochemical performance in half-cell configurations. All-fiber LIB can be successfully assembled by twisting the as-printed LFP and LTO fibers together with gel polymer as the quasi-solid electrolyte. The all-fiber device exhibits a high specific capacity of ≈110 mAh g−1 at a current density of 50 mA g−1 and maintains a good flexibility of the fiber electrodes, which can be potentially integrated into textile fabrics for future wearable electronic applications. [ABSTRACT FROM AUTHOR]

Lateral surface etching of two-dimensional (2D) nanosheets results in holey 2D nanosheets that have abundant edge atoms. Recent reports on holey graphene showed that holey 2D nanosheets can outperform their intact counterparts in many potential applications such as energy storage, catalysis, sensing, transistors, and molecular transport/separation. From both fundamental and application perspectives, it is desirable to obtain holey 2D nanosheets with defined hole morphology and hole edge structures. This remains a great challenge for graphene and is little explored for other 2D nanomaterials. Here, a facile, controllable, and scalable method is reported to carve geometrically defined pit/hole shapes and edges on hexagonal boron nitride (h-BN) basal plane surfaces via oxidative etching in air using silver nanoparticles as catalysts. The etched h-BN was further purified and exfoliated into nanosheets that inherited the hole/edge structural motifs and, under certain conditions, possess altered optical bandgap properties likely induced by the enriched zigzag edge atoms. This method opens up an exciting approach to further explore the physical and chemical properties of hole- and edge-enriched boron nitride and other 2D nanosheets, paving the way toward applications that can take advantage of their unique structures and performance characteristics. [ABSTRACT FROM AUTHOR]

[Display omitted] • The double-layer structure of Li 2 C 4 O 4 -Super P modified separator was constructed. • The great adsorption and catalytic ability are achieved by the synergistic effect of Li 2 C 4 O 4 and Super P. • The Li 2 C 4 O 4 -Super P modified separator exhibits fantastic cycling performance. Lithium-sulfur (Li-S) batteries have been considered as satisfying energy storage devices, but the electrochemical performance of Li-S batteries is severely hindered by the shuttle effect and the sluggish sulfur redox kinetics. Herein, a double-layer separator modified with Li 2 C 4 O 4 and Super P through a simple coating method is prepared. The composite Li 2 C 4 O 4 -Super P exhibits great adsorption on polysulfides. Besides, the combination of Li 2 C 4 O 4 and Super P can reduce charge transfer resistance and improve Li+ transport ability. The Li 2 C 4 O 4 -Super P@PP cell shows an extremely low capacity decay rate of 0.045 % after 800 cycles at 1C and a fantastic capacity of 588.1 mAh·g−1 under the high rate of 5C. [ABSTRACT FROM AUTHOR]

Aqueous Zn-ion batteries have gradually become a suitable choice for large-scale energy storage systems owing to their safety and lower cost. However, Zn metal anodes typically suffer from uneven electrodeposition and zinc dendrite formation, which restricts Zn-ion batteries from being used in further applications. To mitigate this problem, a simple and quick chemical surface modification is employed to construct a multifunctional hybrid interface consisting of ZnF 2 and Sn on the surface of the Zn metal anode. ZnF 2 show a low diffusion energy barrier for Zn2+, effectively shield the direct corrosive reaction from the aqueous electrolyte, and simultaneously increase the hydrogen evolution potential of the Zn electrode. Furthermore, the Sn particles provide a large number of nucleation sites and charge centers, avoiding the direct growth of dendrites. The interface-modified Zn anode achieve stable cycles of 700 h and 500 h at high current densities of 5 and 10 mA/cm2, respectively, while the assembled Zn@ZnF 2 –Sn||V 2 O 5 full battery achieve over 400 stable cycles at 1 A/g. This work uncover the internal mechanism of inhibiting Zn dendrites by the multifunctional interface, providing a means for stabilizing the Zn anode under practical conditions. A multifunctional ZnF 2 –Sn interface was constructed as a surface protective layer via a displacement reaction on zinc metal anode. Such a protective layer can provide a large number of nucleation sites and lower the diffusion barrier of zinc ions, thereby inducing stable deposition of Zn2+ ions. The Zn anode treated by this facile method achieves an excellent aqueous zinc-ion battery. [Display omitted] • Fast solution processing of zinc anodes constructs a multifunctional interface. • ZnF 2 is an multifunctional interface composition with low diffusion barrier. • Tin acts as charge centers and provides nucleation sites for zinc ions. • Multifunctional interface enables synergistic stabilization of zinc anodes. [ABSTRACT FROM AUTHOR]

Low energy density hinders the development of supercapacitors in the market of large hybrid power equipment and electric vehicles that demand much higher energy density. Herein, we conduct a facile and environmentally friendly method to modify the electrodes of supercapacitors through coating a dielectric thin film by atomic layer deposition (ALD) technique, which profoundly improves the electrochemical performance of the electrodes. In specific, the gravimetric capacitance of the ALD-Ti modified electrodes is characterized by 35% significant promotion comparing to the commercialized pristine counterparts, and the operational voltage window of the ALD treated electrodes can expand to 3.5 V using organic electrolyte with remarkable capacitance retention (over 83%) even after 20000 cycles. Besides, appropriate models are established to discuss the detailed charge storage mechanism and possible reasons for good stability of modified electrodes under higher operational voltage. Moreover, the excellent rate and cycling performance of ALD modified electrodes in flexible electrochemical double-layer capacitor (EDLCs) at the bending state substantiates the application superiority of ALD modified electrodes in flexible devices. The unusual combination of charge storage mechanisms of dielectric capacitors and EDLCs established in our work represents specific properties in great need for energy storage applications. Atomic Layer Deposition technique is utilized to modify the electrodes in supercapacitors, the modified electrodes can endure the electrochemical window of 3.5 V in organic electrolyte and possesses 35% higher capacitance compared to pristine carbon electrode with longer lifespan. [Display omitted] • The modified electrode increases 35% higher capacitance compared to original one. • The voltage window of treated electrode extends to 3.5 V in organic electrolyte. • The modified flexible devices demonstrate excellent cycling performance. [ABSTRACT FROM AUTHOR]