Elemental Selenium for Electrochemical Energy Storage

Guidelines and trends for next-generation rechargeable lithium and lithium-ion batteries

This review article summarizes the current trends and provides guidelines towards next-generation rechargeable lithium and lithium-ion battery chemistries.

Elemental selenium enables enhanced water oxidation electrocatalysis of NiFe layered double hydroxides

The oxygen evolution reaction (OER) is involved in various renewable energy systems, such as water-splitting, metal-air batteries and CO₂ electroreduction. Ni-Fe layered double hydroxides (LDHs) have been reported as promising OER electrocatalysts in alkaline electrolytes. Herein, we demonstrate that the introduction of elemental selenium (Se) with an optimized phase composition, i.e., monoclinic (m-) or trigonal (t-) Se, could effectively tailor the OER activity of NiFe-LDH. Compared to t-Se doped NiFe-LDH, the presence of hybrid m/t-Se could effectively tune the electronic states of Ni-O and Fe-O sites, promote the generation of OER-active γ-NiOOH, and inhibit Fe-migration during the OER process, thus enhancing the OER performance. The optimized Ni_0.8Fe_0.2-m/t-Se_0.02-LDH catalyst exhibits extraordinarily high OER activity, with an overpotential of 200 mV at 10 mA cm^-2, which is superior to those of IrO₂ and most of the reported Se-based OER catalysts. The Ni_0.8Fe_0.2-m/t-Se_0.02-LDH catalyst is further implemented as an anode for overall water splitting and demonstrates a low cell voltage of 1.50 V to achieve 10 mA cm^-2.

Implementing Lateral MoSe2 P-N Homojunction by Efficient Carrier-Type Modulation

High-performance p-n junctions based on atomically thin two-dimensional (2D) materials are the fundamental building blocks for many nanoscale functional devices that are ideal for future electronic and optoelectronic applications. The lateral p-n homojunctions with conveniently tunable band offset outperform vertically stacked ones, however, the realization of lateral p-n homojunctions usually require efficient carrier-type modulation in a single 2D material flake, which remains a tech challenge. In this work, we have realized effective carrier-type modulation in a single MoSe₂ flake, and thus, a lateral MoSe₂ p-n homojunction is achieved by sequential treatment of air rapid thermal annealing and triphenylphosphine (PPh₃) solution coating. The rapid thermal annealing modulates MoSe₂ flakes from naturally n-type doping to degenerated p-type doping and improves the hole mobility of the MoSe₂ field effect transistors from 0.2 to 71.5 cm²·V^-1·s^-1. Meanwhile, the n-doping of MoSe₂ is increased by drop-coating PPh₃ solution on the MoSe₂ surface with increased electron mobility from 78.6 to 412.8 cm²·V^-1·s^-1. The as-fabricated lateral MoSe₂ p-n homojunction presents a high rectification ratio of 10⁴, an ideality factor of 1.2, and enhanced photoresponse of 1.3 A·W^-1 to visible light. This efficient carrier-type modulation within a single MoSe₂ flake has potential for use in various functional devices.

Vapor-Infiltration Approach toward Selenium/Reduced Graphene Oxide Composites Enabling Stable and High-Capacity Sodium Storage

Emerging sodium-selenium batteries suffer from volume expansion of the selenium cathode and shuttling effects of soluble intermediates. Confining selenium within the carbon matrix is the most adopted strategy to address these two issues, which is generally realized via a melt-infusion method. Herein, we developed a vapor-infiltration method to fabricate selenium/carbon composites that are advantageous over the melt-infusion route in terms of several aspects: it relieves the requirement of intensive mechanical mixing and simplifies the ratio optimization between selenium and carbon; it avoids selenium aggregation and makes it possible to utilize all of the surface and pores of the carbon host. Utilizing this method, we fabricated a selenium/graphene composite from thermally reduced graphene oxide with a selenium loading equal to 71 wt %, thus approaching the record value. The obtained composite achieved the highest reported to date initial Coulombic efficiency of 88% among various selenium cathodes, with superior rate and cycle performance (410 and 367 mA h g^-1 at 0.1 and 1 A g^-1; capacity decay <10% after 800 cycles at 2 A g^-1) enabled by the supporting graphene framework and the use of the ether electrolyte. In view of the distinct advantages of the vapor-infiltration method and the significant influence of the ether electrolyte on both initial Coulombic efficiency and cyclability of the batteries, we believe the introduced approach will be frequently adopted to incorporate selenium into various host materials, and the ether electrolyte will be widely considered for selenium-based electrodes.

Selenium contamination, consequences and remediation techniques in water and soils: A review

Selenium (Se) contamination in surface and ground water in numerous river basins has become a critical problem worldwide in recent years. The exposure to Se, either direct consumption of Se or indirectly may be fatal to the human health because of its toxicity. The review begins with an introduction of Se chemistry, distribution and health threats, which are essential to the remediation techniques. Then, the review provides the recent and common removal techniques for Se, including reduction techniques, phytoremediation, bioremediation, coagulation-flocculation, electrocoagulation (EC), electrochemical methods, adsorption, coprecipitation, electrokinetics, membrance technology, and chemical precipitation. Removal techniques concentrate on the advantages, drawbacks and the recent achievements of each technique. The review also takes an overall consideration of experimental conditions, comparison criteria and economic aspects.

Three-Dimensional Hierarchical Framework Assembled by Cobblestone-Like CoSe2@C Nanospheres for Ultrastable Sodium-Ion Storage

Sodium-ion batteries (SIBs), as the promising commercial energy system, are restricted by their sluggish kinetics and low sodium-ion storage. Metal selenide possesses good conductivity and capacity but still suffers from the stacked problem and volume expansion. Significantly, CoSe₂/C is successfully prepared with the assistance of citric acid as both a chelating agent and carbon precursor, displaying that cobblestone-like nanospheres with the radii (<25 nm) distribute uniformly in the carbon matrix. It is expected that the established Co-O-C bonds enhance the stability of the structure with faster ion shuttling. With the available electrolyte (NaCF₃SO₃/diethylene glycol dimethyl ether) in a potential window range from 0.5 to 3.0 V, the as-obtained sample shows the ultralong lifespan at 4.5 A g^-1, retaining a capacity of 345 mA h g^-1 after 10 000 cycles. From the detailed kinetic analysis, it is clear that the surface-controlled electrochemical behavior mainly contributes to the excellent large-current cycling stability and Na storage capacity. The ex situ results support that the crystal and morphological structure remains stable. This work is anticipated to enhance the in-depth understanding of the CoSe₂/C anode and supply a facile manner to obtain electrode materials for SIBs.

A high-performance sodium anode composed of few-layer MoSe2 and N, P doped reduced graphene oxide composites

Capacity and stability enhancement has been observed for MoSe₂ covered with N, P-doped rGO sheets. The sodiation behaviour was also investigated through different ex situ studies.

Mixture is better: enhanced electrochemical performance of phenyl selenosulfide in rechargeable lithium batteries

Phenyl selenosulfide is synthesized by an exchange reaction, which shows better performance than the two precursors in rechargeable lithium batteries.

Mesoporous Carbon@Titanium Nitride Hollow Spheres as an Efficient SeS2 Host for Advanced Li-SeS2 Batteries

The introduction of a certain proportion of selenium into sulfur-based cathodes is an effective strategy for enhancing the integrated battery performance. However, similar to sulfur, selenium sulfide cathodes suffer from poor cycling stability owing to the dissolution of reaction intermediate products. In this study, to exploit the advantages of SeS₂ to the full and avoid its shortcomings, we designed and synthesized a hollow mesoporous carbon@titanium nitride (HMC@TiN) host for loading 70 wt % of SeS₂ as a cathode material for Li-SeS₂ batteries. Benefiting from both physical and chemical entrapment by hollow mesoporous carbon and TiN, the HMC@TiN/SeS₂ cathode manifests high utilization of the active material and excellent cycling stability. Moreover, it exhibits promising areal capacity (up to 4 mAh cm^-2 ) with stable cell performance in the high-mass-loading electrode.

High-Performance Li-Se Batteries Enabled by Selenium Storage in Bottom-Up Synthesized Nitrogen-Doped Carbon Scaffolds

Selenium (Se) has great promise to serve as cathode material for rechargeable batteries because of its good conductivity and high theoretical volumetric energy density comparable to sulfur. Herein, we report the preparation of mesoporous nitrogen-doped carbon scaffolds (NCSs) to restrain selenium for advanced lithium-selenium (Li-Se) batteries. The NCSs synthesized by a bottom-up solution-phase method have graphene-like laminar structure and well-distributed mesopores. The unique architecture of NCSs can severe as conductive framework for encapsulating selenium and polyselenides, and provide sufficient pathways to facilitate ion transport. Furthermore, the laminar and porous NCSs can effectively buffer the volume variation during charge/discharge processes. The integrated composite of Se-NCSs has a high Se content and can ensure the complete electrochemical reactions of Se and Li species. When used for Li-Se batteries, the cathodes based on Se-NCSs exhibit high capacity, remarkable cyclability, and excellent rate performance.

Recent Progress in the Design of Advanced Cathode Materials and Battery Models for High-Performance Lithium-X (X = O2 , S, Se, Te, I2 , Br2 ) Batteries

Recent advances and achievements in emerging Li-X (X = O₂ , S, Se, Te, I₂ , Br₂ ) batteries with promising cathode materials open up new opportunities for the development of high-performance lithium-ion battery alternatives. In this review, we focus on an overview of recent important progress in the design of advanced cathode materials and battery models for developing high-performance Li-X (X = O₂ , S, Se, Te, I₂ , Br₂ ) batteries. We start with a brief introduction to explain why Li-X batteries are important for future renewable energy devices. Then, we summarize the existing drawbacks, major progress and emerging challenges in the development of cathode materials for Li-O₂ (S) batteries. In terms of the emerging Li-X (Se, Te, I₂ , Br₂ ) batteries, we systematically summarize their advantages/disadvantages and recent progress. Specifically, we review the electrochemical performance of Li-Se (Te) batteries using carbonate-/ether-based electrolytes, made with different electrode fabrication techniques, and of Li-I₂ (Br₂ ) batteries with various cell designs (e.g., dual electrolyte, all-organic electrolyte, with/without cathode-flow mode, and fuel cell/solar cell integration). Finally, the perspective on and challenges for the development of cathode materials for the promising Li-X (X = O₂ , S, Se, Te, I₂ , Br₂ ) batteries is presented.

Graphitic Nanocarbon-Selenium Cathode with Favorable Rate Capability for Li-Se Batteries

A well-organized selenium/carbon nanosheets nanocomposite(Se/CNSs) is prepared by confining chain-like Se_n molecules in hierarchically micromesoporous carbon nanosheets. A unique two-dimensional morphology and high graphitization degree of carbon nanosheets benefits fast Li⁺/e^- access to the active Se, which guarantees a high utilization of Se during the(de)lithiation process. Besides, the chain-like Se molecules confined in the carbon matrix could alleviate the shuttle effect of polyselenides and promise a stable electrochemistry. Therefore, the resultant Se/CNSs delivers a highly reversible capacity, a long cycle life and favorable rate capabilities. Furthermore, a Li-Se pouch cell built from a metallic Li anode and the as-prepared Se/CNSs cathode exhibits an excellent electrochemical performance, demonstrating the potential of Se/CNSs in serving future energy storage devices with high energy density.

A review of flexible lithium–sulfur and analogous alkali metal–chalcogen rechargeable batteries

This review summarizes recent progress in flexible Li–S and analogous alkali metal–chalcogen batteries, including flexible chalcogen cathodes, flexible alkali metal anodes, flexible solid-state electrolytes, and flexible battery prototypes.

Li3Ge3Se6: the first ternary lithium germanium selenide with interesting∞[Ge6Se12]nchains constructed by ethane-like [Ge2Se6]6−clusters

The first lithium germanium selenide, Li₃Ge₃Se₆with the first discovered chain formed by [Ge₂Se₆]⁶⁻clusters in the [Li₃Se₆] tunnels.

Heteroatomic SenS8-n Molecules Confined in Nitrogen-Doped Mesoporous Carbons as Reversible Cathode Materials for High-Performance Lithium Batteries

A reversible cathode material in an ether-based electrolyte for high-energy lithium batteries was successfully fabricated by homogeneously confining heteroatomic SenS8-n molecules into nitrogen-doped mesoporous carbons (NMCs) via a facile melt-impregnation route. The resultant SenS8-n/NMC composites exhibit highly reversible electrochemical behavior, where selenium sulfides are recovered through the reversible conversion of polysulfoselenide intermediates during discharge-charge cycles. The recovery of selenium sulfide molecules endows the SenS8-n/NMC cathodes with the rational integration of S and Se cathodes. Density functional theory calculations further reveal that heteroatomic selenium sulfide molecules with higher polarizability could bind more strongly with NMCs than homoatomic sulfur molecules, which provides more efficient suppression of the shuttling phenomenon. Therefore, with further assistance of mesopore confinement of the nitrogen-doped carbons, the Se2S6/NMC composite with an optimal Se/S mole ratio of 2/6 presents excellent cycle stability with a high initial Coulombic efficiency of 96.5% and a high reversible capacity of 883 mAh g(-1) after 100 cycles and 780 mAh g(-1) after 200 cycles at 250 mA g(-1). These encouraging results suggest that the heteroatomization of chalcogen (such as S, Se, or Te) molecules in mesostructured carbon hosts is a promising strategy in enhancing the electrochemical performances of chalcogen/carbon-based cathodes for Li batteries.

Two dimensional layered Co0.85Se nanosheets as a high-capacity anode for lithium-ion batteries

In recent years, two-dimensional (2D) layered transitional metal chalcogenides (TMCs) have received much attention as promising electrode materials in energy storage. Although recent reports on 2D TMC nanostructures have demonstrated promising electrochemical performances, the major scientific challenge is to develop a viable synthesis process to produce layered structures of chalcogenides (Co, Ni or Fe based TMCs) as anode materials. In this work, we propose the synthesis of layered Co0.85Se nanosheets in a solution based method by using a 2D oriented attachment strategy. The as-prepared Co0.85Se nanosheets exhibit specific capacities as high as 675 mA h g(-1) at 100 mA g(-1). When the current densities were further increased to 200, 500 and 1000 mA g(-1), the reversible capacities can still reach up to 645, 574 and 493 mA h g(-1) with excellent cycling life of 95, 85 and 73%, respectively. Li-ion storage performance of layered Co0.85Se nanosheets is higher than that of Co0.85Se microspheres as well as cobalt sulfide. The superior electrochemical performance of Co0.85Se nanosheets is attributed to their 2D layered structure which enhances electrical conductivity and improves diffusion pathways of the Li-ion within the host material. The synthesis method described in this work serves as a general route for the design and preparation of other 2D layered TMCs.

Multifunctional Nitrogen-Doped Loofah Sponge Carbon Blocking Layer for High-Performance Rechargeable Lithium Batteries

Low-cost, long-life, and high-performance lithium batteries not only provide an economically viable power source to electric vehicles and smart electricity grids but also address the issues of the energy shortage and environmental sustainability. Herein, low-cost, hierarchically porous, and nitrogen-doped loofah sponge carbon (N-LSC) derived from the loofah sponge has been synthesized via a simple calcining process and then applied as a multifunctional blocking layer for Li-S, Li-Se, and Li-I2 batteries. As a result of the ultrahigh specific area (2551.06 m(2) g(-1)), high porosity (1.75 cm(3) g(-1)), high conductivity (1170 S m(-1)), and heteroatoms doping of N-LSC, the resultant Li-S, Li-Se, and Li-I2 batteries with the N-LSC-900 membrane deliver outstanding electrochemical performance stability in all cases, i.e., high reversible capacities of 623.6 mA h g(-1) at 1675 mA g(-1) after 500 cycles, 350 mA h g(-1) at 1356 mA g(-1) after 1000 cycles, and 150 mA h g(-1) at 10550 mA g(-1) after 5000 cycles, respectively. The successful application to Li-S, Li-Se, and Li-I2 batteries suggests that loofa sponge carbon could play a vital role in modern rechargeable battery industries as a universal, cost-effective, environmentally friendly, and high-performance blocking layer.

Biomagnetic Recovery and Bioaccumulation of Selenium Granules in Magnetotactic Bacteria

Using microorganisms to remove waste and/or neutralize pollutants from contaminated water is attracting much attention due to the environmentally friendly nature of this methodology. However, cell recovery remains a bottleneck and a considerable challenge for the development of this process. Magnetotactic bacteria are a unique group of organisms that can be manipulated by an external magnetic field due to the presence of biogenic magnetite crystals formed within their cells. In this study, we demonstrated an account of accumulation and precipitation of amorphous elemental selenium nanoparticles within magnetotactic bacteria alongside and independent of magnetite crystal biomineralization when grown in a medium containing selenium oxyanion (SeO3 (2-)). Quantitative analysis shows that magnetotactic bacteria accumulate the largest amount of target molecules (Se) per cell compared with any other previously reported nonferrous metal/metalloid. For example, 2.4 and 174 times more Se is accumulated than Te taken up into cells and Cd(2+) adsorbed onto the cell surface, respectively. Crucially, the bacteria with high levels of Se accumulation were successfully recovered with an external magnetic field. The biomagnetic recovery and the effective accumulation of target elements demonstrate the potential for application in bioremediation of polluted water.

IMPORTANCE

The development of a technique for effective environmental water remediation is urgently required across the globe. A biological remediation process of waste removal and/or neutralization of pollutant from contaminated water using microorganisms has great potential, but cell recovery remains a bottleneck. Magnetotactic bacteria synthesize magnetic particles within their cells, which can be recovered by a magnetic field. Herein, we report an example of accumulation and precipitation of amorphous elemental selenium nanoparticles within magnetotactic bacteria independent of magnetic particle synthesis. The cells were able to accumulate the largest amount of Se compared to other foreign elements. More importantly, the Se-accumulating bacteria were successfully recovered with an external magnetic field. We believe magnetotactic bacteria confer unique advantages of biomagnetic cell recovery and of Se accumulation, providing a new and effective methodology for bioremediation of polluted water.

Superior Na-ion storage properties of high aspect ratio SnSe nanoplates prepared by a spray pyrolysis process

SnSe nanoplates with thin and uniform morphology are prepared by one-pot spray pyrolysis, and are examined as anode materials for Na-ion batteries. During the spray pyrolysis process, metallic Se and Sn are prepared from SeO2 and SnO2, respectively, under a reducing atmosphere. Metallic Sn and metalloid Se, with melting points of 232 and 221 °C, respectively, form a melted Sn-Se mixture, which reacts exothermally to form SnSe nanocrystals. Several of these nanocrystals are grown simultaneously forming a micron-sized powder. Complete elimination of the excess amount of metalloid Se, by forming H2Se gas, results in aggregation-free SnSe nanoplates. The aspect ratio of these nanoplates is as high as 11.3. The discharge capacities for the SnSe nanoplates, prepared from spray solutions containing 100, 400, and 800% of the stoichiometric SeO2 content needed to form SnSe, are 407, 558, and 211 mA h g(-1), respectively, after 50 cycles at a constant current density of 0.3 A g(-1); their capacity retentions calculated from the second cycle onwards are 77, 100, and 60%, respectively. The phase pure SnSe nanoplates with a high aspect ratio show good cycling and rate performances for Na-ion storage.

Insight into the Capacity Fading Mechanism of Amorphous Se2S5 Confined in Micro/Mesoporous Carbon Matrix in Ether-Based Electrolytes

In contrast to the stable cycle performance of space confined Se-based cathodes for lithium batteries in carbonate-based electrolytes, their common capacity fading in ether-based electrolytes has been paid less attention and not yet well-addressed so far. In this work, the lithiation/delithiation of amorphous Se2S5 confined in micro/mesoporous carbon (Se2S5/MPC) cathode was investigated by in situ X-ray near edge absorption spectroscopy (XANES) and theoretical calculations. The Se2S5/MPC composite was synthesized by a modified vaporization-condensation method to ensure a good encapsulation of Se2S5 into the pores of MPC host. In situ XANES results illustrated that the lithiation/delithiation reversibility of Se component was gradually decreased in ether-based electrolytes, leading to an aggravated formation of long-chain polyselenides during cycling and further capacity decay. Moreover, ab initio calculations revealed that the binding energy of polyselenides (Li2Sen) with carbon host is in an order of Li2Se6 > Li2Se4 > Li2Se. The insights into the failure mechanism of Se-based cathode gain in this work are expected to serve as a guide for future design on high performance Se-based cathodes.

Fullerene-like MoSe2 nanoparticles-embedded CNT balls with excellent structural stability for highly reversible sodium-ion storage

Three-dimensional (3D) porous-structured carbon nanotube (CNT) balls embedded with fullerene-like MoSe2 nanocrystals were successfully prepared by the spray pyrolysis process and subsequent selenization process. The MoO2-CNT composite balls prepared by spray pyrolysis transformed into the fullerene-like MoSe2/CNT (F-MoSe2/CNT) composite balls by the selenization process. The F-MoSe2/CNT composite balls exhibited superior sodium-ion storage properties to bare MoSe2 and MoSe2/CNT with a filled structure (N-MoSe2/CNT), both of which were prepared as comparison samples. The 250(th) discharge capacities of bare MoSe2, N-MoSe2/CNT composite balls, and F-MoSe2/CNT composite balls were 144, 200, and 296 mA h g(-1), respectively, at a high current density of 1.0 A g(-1), and their capacity retentions measured from the second cycle were 37%, 66%, and 83%, respectively. The 10(th) discharge capacities of the F-MoSe2/CNT composite balls were 382, 346, 310, 280, and 255 mA h g(-1) at current densities of 0.2, 0.5, 1.5, 3.0, and 5.0 A g(-1), respectively. The synergetic effect of the fullerene-like MoSe2 nanocrystals with ultrafine sizes and the CNT balls with a tangled and 3D porous structure and high electrical conductivity resulted in excellent sodium-ion storage properties of the F-MoSe2/CNT composite balls.

Facile synthesis of selenium/potassium tartrate derived porous carbon composite as an advanced Li–Se battery cathode

The element Se with amorphous structure is uniformly encapsulated into the porous (micro- and small meso-porous) structure of potassium tartrate derived carbon, the obtained Se/C composite show good electrochemical performance.

One-step microwave synthesized core–shell structured selenium@carbon spheres as cathode materials for rechargeable lithium batteries

The core–shell structure greatly suppressed the shuttle effect of the lithium–selenium battery and the robust carbon shells could remain unbroken even after 100 cycles and flexibly accommodate to the volume change of selenium cores.

High-Capacity Te Anode Confined in Microporous Carbon for Long-Life Na-Ion Batteries

Sodium-ion batteries (SIBs) have attracted considerable attention as an alternative energy-storage technology in recent years. Developing advanced sodium storage anode materials with appropriate working potential, high capacity, and good cycling performance is very important. Herein, we demonstrate a nanostructured tellurium@carbon (nano-Te@C) composite by confining nano-Te molecules in the space of carbon micropores as an attractive anode material for SIBs. The nano-Te@C anode presents an appropriate redox potential in the range of 1.05-1.35 V (vs Na(+)/Na), which avoids the Na dendrite problem and achieves a high reversible capacity of 410 mA h g(-1) on the basis of a two-electron redox reaction mechanism. Notably, the nano-Te@C exhibits an admirable long-term cycling stability with a high capacity retention of 90% for 1000 cycles (i.e., ultralow capacity decay of 0.01% per cycle). The excellent electrochemical property of nano-Te@C benefits from the high electroactivity from the nanostructure design and the effective confinement of the microporous carbon host. In addition, a Na-ion full cell by using nano-Te@C as anode and Na2/3Ni1/3Mn2/3O2 as cathode is demonstrated for the first time and exhibits a remarkable capacity retention up to 95% after 150 cycles. The results put new insights for the development of advanced SIBs with long-cycle lifespan.

Accommodating lithium into 3D current collectors with a submicron skeleton towards long-life lithium metal anodes

Lithium metal is one of the most attractive anode materials for electrochemical energy storage. However, the growth of Li dendrites during electrochemical deposition, which leads to a low Coulombic efficiency and safety concerns, has long hindered the application of rechargeable Li-metal batteries. Here we show that a 3D current collector with a submicron skeleton and high electroactive surface area can significantly improve the electrochemical deposition behaviour of Li. Li anode is accommodated in the 3D structure without uncontrollable Li dendrites. With the growth of Li dendrites being effectively suppressed, the Li anode in the 3D current collector can run for 600 h without short circuit and exhibits low voltage hysteresis. The exceptional electrochemical performance of the Li-metal anode in the 3D current collector highlights the importance of rational design of current collectors and reveals a new avenue for developing Li anodes with a long lifespan.

A major problem with the use of lithium metal as the battery anode is the undesired lithium dendrite formation during cycling. Here, the authors show that the problem can be mitigated with a carefully designed three-dimensional porous current collector.

Localized polyselenides in a graphene-coated polymer separator for high rate and ultralong life lithium–selenium batteries

A graphene-coated polymer separator was developed for lithium–selenium batteries with pure selenium powder as the active material.

A selenium-confined porous carbon cathode from silk cocoons for Li–Se battery applications

A composite of selenium (Se) and a rich porous carbon material (PCM) with mesopores from silk cocoons is explored as a cathode for lithium–selenium (Li–Se) batteries for the first time.