Superb Electrochemical Performance Research Articles

In-situ synthesis of porous metal fluoride@carbon composite via simultaneous etching/fluorination enabled superior Li storage performance

Transition metal fluorides as Li-free conversion-type cathode materials have high theoretical specific capacities, however, their preparation strategy, sluggish electrochemical kinetic and poor cyclability have impeded their wide adoption in lithium-ion batteries. Herein, a facile in-situ synthesis of porous metal-fluoride-carbon composites is accomplished via simultaneous polytetrafluorethylene-based hard template etching and metal fluorination. This not only facilitates fast electron transfer and lithium-ion diffusion kinetics, but also buffers severe volume fluctuation during lithiation/delithation and enables the formation of a uniform and thin Li2CO3/LiF-rich cathode-electrolyte interphase. As a proof of concept, the as-prepared porous FeF3 @C (p-FeF3 @C) indeed exhibits a high specific capacity of 230 mAh g−1 at 0.1 C together with an excellent capacity retention of 92.5% at 1 C for 200-cycles. Moreover, the practicality of the strategy is demonstrated by the superb electrochemical performance of the full-cells coupled with pre-lithiated graphite anodes. Therefore, the proposed novel synthetic strategy will enlighten the future design of high-performance metal-fluoride-carbon composites with porous structure for energy storage applications.

Pore size distribution modulation of waste cotton-derived carbon materials via citrate activator to boost supercapacitive performance

Structural engineering involving pore configuration tuning and specific surface area enhancement is an effective strategy to improve the electrochemical properties of carbon-based capacitors. Herein, the hierarchical porous carbons are extracted from natural waste cottons as advanced electrode materials for supercapacitors via facile carbonization and citrate modification processes. The optimal PC-K (porous carbon with potassium citrate as activator) sample is equipped with remarkable mesopore configuration (1292.9 m2 g−1), considerable specific surface area (1727.9 m2 g−1) and even premier heteroatom content (17.1 at%), owing to the well-designed structural engineering. Further, it displays superb electrochemical performances including high capacity of 273.7 F g−1 at 1.0 A g−1 (maintaining 203.8 F g−1 at 10 A g−1), and long cycling stability with 97.49% capacitance retention after 8000 charge/discharge cycles at 10 A g−1, indicating the significant application potential. Simultaneously, the maximum energy density reaches almost 9.93 Wh kg−1 at a power density of 350 W kg−1 in the two-electrode device. Extensive source, inexpensive cost, and superior electrochemical performances unambiguously suggest that the cotton-derived hierarchical porous carbon materials can be rendered great practical value and broad prospects for supercapacitors.

Conformal Lithium Peroxide Growth Kinetically Driven by MoS2/MoN Heterostructures Towards High‐Performance Li−O2 Batteries

AbstractThe morphological control and spatial accommodation of Li2O2 discharge products on the oxygen cathode are crucial to bolstering both the Coulombic and round‐trip efficiencies of Li−O2 batteries. Herein, MoS2/MoN heterostructures are constructed on carbon cloth to serve as the freestanding and binder‐free oxygen cathode for Li−O2 batteries, lending a low charge/discharge polarization of 0.79 V, a large specific capacity of 9.04 mAh cm−2, and a superb cycling stability beyond 800 h. Through comprehensive microscopic, electroanalytical and density function theory analyses, the superb electrochemical performance is attributed to the formation of a conformal and amorphous Li2O2 layer, which is kinetically driven in virtue of the higher electric conductivity of MoN and stronger LiO2 intermediate adsorption on the heterostructures. This work advocates the merits of interfacial engineering to enhance the performance of Li−O2 batteries by manipulating the discharge product formation.

Multi-scale self-templating synthesis strategy of lignin-derived hierarchical porous carbons toward high-performance zinc ion hybrid supercapacitors

Chemical activation is a common process for preparing porous carbon electrode materials of supercapacitors. Nevertheless, chemical activation approach has the disadvantages of being chemically caustic, environmentally unfriendly, and expensive. This study constitutes a multi-scale self-template approach for the preparation of lignin-derived hierarchical porous carbons (LHPCs) with high specific surface areas and excellent electrochemical performances. KCl, carbonates, and sulfates, generated in the carbonization process, play the role of multi-scale template agents for the pore-forming process. LHPCs exhibited superb electrochemical performances as electrodes of supercapacitors with alkaline and neutral sulfate electrolytes. In addition, the Zn//LHPCs hybrid supercapacitors (ZIHSCs) achieved an ultra-high energy density of 135 Wh kg−1, which is 20 times higher than symmetric supercapacitors with KOH electrolytes (6.6 Wh kg−1) and 9 times higher than symmetric supercapacitors with Na2SO4 electrolyte (14.8 Wh kg−1). This work proposes a general multi-scale self-template strategy for the synthesis of hierarchical porous carbons from sodium lignosulfonate for supercapacitor applications.

Fabricating of N/O-codoping porous carbon interpenetrating networks for high energy aqueous supercapacitor

Developing high-capacity carbon electrodes with an enlarged potential window is a significant strategy for high energy aqueous supercapacitor. However, engineering synthesis of hierarchical porous carbon networks with the broad electrochemical stability window remains a great challenge. In this work, N/O codoped hierarchical porous carbon networks (MPBx) are constructed based on Schiff-base reaction for the purpose of excellent charge storage and kinetics of electrolyte ions diffusion in “water-in-salt” (lithium bis(trifluoromethane sulfonyl)imide, LiTFSI) electrolyte. When fabricated as an electrode for symmetrical supercapacitor, the 2.25 V LiTFSI-based supercapacitor exploits a superior specific capacitance (180 F g−1, 0.5 A g−1) and an exceptional energy delivery of 31.7 W h kg−1 at the corresponding power output of 562 W kg−1, together with an impressive cycling stability with 93.8 % capacitance retention after 10,000 continuous cycles. The improvement in the superb electrochemical performance can be attributed to the excellent conductive networks, high ion-adsorption area (1902 m2 g−1), interpenetrating porous architecture (macro-, meso- and micropore) and high-level heteroatoms dopants (N: 2.56 at.%, O: 11.46 at.%). The excellent electrochemical performances demonstrate that the carbon networks hold great prospects for promoting the energy delivery of aqueous supercapacitors.

Composite Assembling of Oxide-Based Optically Transparent Electrodes for High-Performance Asymmetric Supercapacitors.

Simultaneously achieving a transparent and high-energy density supercapacitor is a major challenge because of the trade-off between energy storage capacity and optical transparency of active electrode materials. Herein, we demonstrate a novel approach to construct an optically transparent asymmetric supercapacitor (Trans-ASC) by assembling positive (ZnO-SnO2) and negative (TiO2-SnO2) composite thin-film electrodes on a conductive indium-doped tin oxide substrate via reactive DC magnetron cosputtering. The optical transmittance for both composite thin films is found to be 68% (ZnO-SnO2) and 64% (TiO2-SnO2). Furthermore, electrochemical kinematics of the primed transparent electrodes are scrutinized in 0.5 M KOH electrolyte without affecting the transparency of active electrodes. The structural reliability of the electrodes aids the superb electrochemical performance to construct a Trans-ASC, TiO2-SnO2//ZnO-SnO2, which works at a voltage of +1.2 V and attains a higher areal capacitance of 44.6 mF cm-2 at 2 mA cm-2. The assembled Trans-ASC delivers a maximum areal energy density of 8.75 μW h cm-2 with an optimal areal power density of 570 μW cm-2. Additionally, the capacitance retention of 81.6% and transparency of both electrodes remain almost the same (up to 60% for ZnO-SnO2 and 62% for TiO2-SnO2) even after 10,000 charging-discharging cycles. These remarkable electrochemical properties and outstanding cycling stability of the designed Trans-ASC device make it a potential candidate for storing energy and for further use in transparent electronic devices.

Highly Flexible and Compressible Zinc-Ion Batteries with Superb Electrochemical Performance Enabled By A Dual Structural Regulation Strategy

Highly Flexible and Compressible Zinc-Ion Batteries with Superb Electrochemical Performance Enabled By A Dual Structural Regulation Strategy

Rational Design of Tungsten Selenide @ N-Doped Carbon Nanotube for High-Stable Potassium-Ion Batteries.

Potassium-ion batteries (PIBs) are deemed as one of the most promising energy storage systems due to their high energy density and low cost. However, their commercial application is far away from satisfactory because of limited suitable electrode materials. Herein, core-shell structured WSe2 @N-doped C nanotubes are rationally designed and synthesized via selenizing WO3 @ polypyrrole for the first time. The large interlayer spacing of WSe2 can facilitate the intercalation/deintercalation of K+ . Meanwhile, the core-shell structured nanotube provides favorable interior void space to accommodate the volume expansion of WSe2 during cycling. Thus, the obtained electrode exhibits superb electrochemical performance with a high capacity of 301.7mAhg-1 at 100mAg-1 over 120 cycles, and 122.1mAhg-1 can remain at 500mAg-1 even after 1300 cycles. Ex-situ X-ray diffraction analysis reveals the K-ion storage mechanism of WSe2 @N-doped C includes intercalation and conversion reaction. Density function theory (DFT) calculation demonstrates the reasonable diffusion pathway of K+ . In addition, the obtained WSe2 @N-doped C nanotubes have been used as anode material for lithium-ion batteries, which also show good rate performance and high cycle stability. Therefore, this work offers a new methodology for the ration design of new structure electrode materials with long cycle stability.

Origin of high electrochemical stability of multi-metal chloride solid electrolytes for high energy all-solid-state lithium-ion batteries

All-solid-state batteries (ASSBs) have gained substantial attention because of their intrinsic safety and potentially high energy density. To enable ASSBs, developing solid-state electrolytes (SSEs) with high electrochemical stability is of foremost significance. Here we report a multi-metal chloride SSEs with an excellent electrochemical stability (up to 4.5 V vs. Li+/Li), which originates from the strong Zr-Cl bonding. In addition, a high room-temperature ionic conductivity of 1.58 mS/cm was achieved via increasing the Li vacancies in the structure as well as balancing carrier and vacancy concentration. Coupled with nickel-rich cathodes (LiNi0.83Co0.12Mn0.05O2) and high-voltage LiCoO2 (4.5 V vs. Li+/Li), ASSBs demonstrated superb electrochemical performance. This work provides an in-depth structural understanding of multi-metal chloride SSEs and feasible strategies to realize high-energy-density ASSBs.

Potassium storage mechanism of In2S3/C nanofibers as the anode for potassium ion batteries

The excellent electrochemical performance of indium sulfide (In2S3) in lithium ion batteries (LIBs) and sodium ion batteries (SIBs) prompted us to explore its energy storage mechanism in potassium ion batteries (PIBs). In this work, In2S3/C nanofibers are successfully synthesized by simple electrospinning and subsequent vulcanization. In K half cells, compared to commercial In2S3 electrodes, In2S3/C nanofibers as anode materials for PIBs show outstanding electrochemical performance, which can deliver reversible capacities of 397.6 (25), 366.2 (50), 335.2 (100), 307.8 (200), 260.4 (500) and 212.2 mAh g−1 (1000 mA g−1), respectively. In K full cells, In2S3/C nanofibers can also show good potassium storage performance and can light up 15 light emitting diodes (LEDs). The superb electrochemical performance of In2S3/C nanofibers is due to the in-situ composite with self-nitrogen-doped carbon matrix and the nanoization of In2S3 particles, which buffers the volume effect and improves the conductivity of the material during the potassium storage process. In addition, the mechanism of potassium storage of In2S3/C nanofibers was systematically studied by cyclic voltammetry (CV), ex-situ XRD, TEM and XPS methods. The mechanism of In2S3 for K-ion storage can be described as the conversion reaction: In2S3 + 6K+ + 6e− ⇌ In + 3K2S.

Electrodeposition of poly(3,4-ethylenedioxythiophene) coated manganese dioxide nanospheres for flexible asymmetric planar supercapacitor with superior energy density

Although planar asymmetric supercapacitors (ASCs) have attracted extensive attentions as prospective microscale energy storage devices, their practical applications are severely confined by the low energy density and inefficient patterning techniques. Herein, poly (3,4-ethylenedioxythiophene) (PEDOT) coated manganese dioxide (MnO2) nanospheres (MnO2@PEDOT) as cathode is firstly fabricated by electrodepositing. Benefitting from the synergistic effect of the nanocomposites, MnO2@PEDOT cathode displays a broad operating voltage from 0 to 1.0 V (vs Ag/AgCl), excellent areal specific capacitance (116.9 mF cm−2 at 0.1 mA cm−2) with outstanding rate capability and cyclic stability. To complement the wide potential of planar ASCs, urchin-like vanadium pentoxide (V2O5) is similarly fabricated as anode with superb electrochemical performance. As a result, the as-assembled V2O5//MnO2@PEDOT planar ASCs show superior characteristics including a stable operating voltage of 1.8 V, commendable energy density of 15.1 μWh cm−2 along with remarkable cycle performance (87.2% retention after 10 000 cycles), and distinguished integrated performance with commercial solar cells, which exceed majority of formerly reported analogous works. Therefore, this work will create new opportunities for high-performance pseudocapacitive planar ASCs to meet the power requirements in wearable and integrated systems.

Lithium‐Sulfur Batteries: An Organodiselenide Comediator to Facilitate Sulfur Redox Kinetics in Lithium–Sulfur Batteries (Adv. Mater. 13/2021)

Redox co-mediation provides an effective approach to promote the reaction kinetics of polysulfides in lithium–sulfur batteries. In article number 2007298, Jia-Qi Huang and co-workers propose an organodiselenide as a redox co-mediator to accelerate the sulfur redox kinetics. The organodiselenide co-mediator endows lithium–sulfur batteries with superb electrochemical performance with high actual energy density of 301 Wh kg−1. This work inspires further exploration in mediating Li–S kinetics for practical high-energy-density batteries.

“Water-In-Salt” Electrolyte-Based High-Voltage (2.7 V) Sustainable Symmetric Supercapacitor with Superb Electrochemical Performance—An Analysis of the Role of Electrolytic Ions in Extending the Cell Voltage

The present research on an aqueous electrolyte(s)-based supercapacitor, considered to be the next-generation storage device, is mainly focused on to achieve a wide potential window with high energy...

Enhanced electrochemical performance of Si-carbon materials from Larch waste by filtration liquefaction residue process

Super-capacitor has been keeping large scientific interest since it was found. In the meantime, how to clever utilize biomass to improve biomass super-capacitor performance still remains challenge. It is notably concern to fabricate Si-carbon materials by efficient utilization of Larch sawdust, and enhance electrochemical performance of Si-carbon by simple process. Here we show, the Si-carbon material was produced from larch liquefaction via liquefaction-filtration-in situ doping-carbonization process, and the hierarchically porous carbon was prepared from larch residue by liquefaction-filtration-KOH activation-carbonization process. The as-prepared materials exhibited superb electrochemical performance. The larch residue-carbon material has certain electrochemical properties (specific capacitance = 211.4 F/g). As well as, the Si-carbon material with abundant porosity (BET = 284.9 m2/g) reveals a high specific capacitance (254.0 F/g), energy density (90.31 Wh/kg) and power density (177.0 W/kg) at a current density of 0.2 A/g in 1 M KOH electrolyte, as well as a good rate performance and stability (with a capacitance retention above 97% after 3000 cycles), the specific capacitance improved by 10% via further filtration process (from 235.5 F/g). Taking a simple liquefaction filtration process improved the efficiency and electrochemical performance of larch sawdust.

The synthesis of carbon microspheres film composed of nano‐onions and its application as flexible supercapacitors

AbstractFlexible electrodes with superior mechanical and electrochemical properties are essential for flexible supercapacitors. A convenient and scalable colloidal film‐assisted chemical vapor deposition (CF‐CVD) method is developed for the one‐step fabrication of the carbon microspheres films composed of carbon nano‐onions (CMS‐CNO films). The influence of growth conditions (such as growth temperature, time, and gas ratio) during CF‐CVD process on the carbon structures and the growth mechanism of the CMS‐CNO films have been investigated. By controlling the growth conditions, the controllable preparation of CMS‐CNO films is realized. Such binder‐free films can be used for the assembly of flexible supercapacitors, and unique architecture can achieve excellent performance. Benefitting from the composite of nano‐micro zero dimensional structures, the performance of the film in supercapacitors is remarkably improved. At the current density of 5 mA cm−2, the area‐specific capacity can be 903 mF cm−2. When the current density is increased to 500 mA cm−2, the area‐specific capacity can be increased to 729 mF cm−2. This simple and low‐cost preparation process and the superb electrochemical performance suggest great potential applications of CMS‐CNO films in flexible supercapacitors.

Low temperature and atmospheric pressure fabrication of Li3VO4/rGO hybrid as high-performance anode for lithium-ion batteries

Li3VO4 particles anchored on reduced graphene oxide hybrid (Li3VO4/rGO) are firstly fabricated through a solvent thermal method at low temperature and atmospheric pressure. In the Li3VO4/rGO, rGO reduces the particle size of Li3VO4 and improves the electronic conductivity of the hybrid, resulting in excellent reaction kinetics and high pseudocapacitive charge storage of 69.3%, giving rise to superb electrochemical performance as anode for Li-ion batteries. After 200 cycles at 0.15 A g−1, the Li3VO4/rGO electrode delivers high discharge capacity of 410.7 mAh g−1, which is distinctly improved than that of pristine Li3VO4 obtained under similar condition (274.1 mAh g−1 after 200 cycles). Moreover, the Li3VO4/rGO electrode also exhibits excellent rate capability, showing high discharge capacity of 249.5 mAh g−1 at a specific current of 1.6 A g−1. The low temperature and atmospheric pressure fabrication approach is easy to scale up, which is advantageous for practical application.

Single-Layer Dititanium Oxide Ti2O MOene: Multifunctional Promises for Electride, Anode Materials, and Superconductor.

Using the first-principles calculations, we report the existence of the single-layer (SL) dititanium oxide Ti2O (labeled as MOene) that constructs a novel family of MXene based on transition-metal oxides. This MOene material strongly contrasts the conventional ones consisting of transition-metal carbides and/or nitrides. SL Ti2O has high thermal and dynamical stabilities because of the strong Ti-O ionic bonding interactions. Moreover, this material is an intrinsic electride and exhibits extremely low diffusion barriers of ∼12.0 and 6.3 meV for Li and Na diffusion, respectively. When applied as anode materials in lithium-ion batteries and sodium-ion batteries, it possesses a high energy storage capacity (960.23 mAhg-1), surpassing the traditional MXenes-based anodes. The superb electrochemical performance stems from the existing anionic electron on Ti2O surface. Astonishingly, SL Ti2O is also determined to be a superconductor with a superconducting transition temperature (Tc) of ∼9.8 K, which originates from the soft-mode of the first acoustic phonon branch and enhanced electron-phonon coupling in the low-frequency region. Furthermore, this soft-mode behaves much softer upon applying a compressive strain of 2%, leading to a higher Tc of 11.9 K. Our finding broadens the family of MXenes and could facilitate more experimental efforts toward future nanodevices.

Magnetic Field Assisted Construction of Hollow Red P Nanospheres Confined in Hierarchical N‐Doped Carbon Nanosheets/Nanotubes 3D Framework for Efficient Potassium Storage

AbstractRed P has drawn extensive attention as a promising low‐cost anode for potassium‐ion batteries (PIBs) thanks to its large theoretical capacity and natural abundance. However, serious pulverization/aggregation issues during consecutive cycles and sluggish kinetics limit its practical commercial applications. Herein, hollow red P nanospheres confined in hierarchical N‐doped carbon nanosheets/nanotubes framework are designed and controllably fabricated via a simple yet efficient magnetic field assisted methodology. The involved magnetic field induced formation mechanism of the 3D hybrid architecture is tentatively put forward here. Comprehensive physicochemical/structural characteristics and theoretical simulation authenticate that the resultant hybrid anode is endowed with exceptional structural/compositional merits, which ameliorate volumetric expansion/compression over potassiation/depotassiation processes, and guarantee abundant active sites, rigid structure stability, and convenient electronic/ionic transport network for efficient potassium storage. As a result, the unique hollow red P based hybrid electrode delivers superb electrochemical performance in both half and full cells in terms of reversible capacities, rate properties, and long‐duration cycling behaviors as a competitive anode toward advanced PIBs. More significantly, this work proposes an innovative strategy for efficient fabrication of hollow red P architectures for next‐generation PIBs and beyond.

P2-type layered structure Na1.0Li0.2Mn0.7Ti0.1O2 as a superb electrochemical performance cathode material for sodium-ion batteries

Abstract P2-type layered structure manganese-based materials have been reported as the most promising candidates for practical applications of sodium ion batteries because of their high capacity, facile fabrication, low cost, and environmental friendliness. In this work, a new P2-type layered structure Na1.0Li0.2Mn0.7Ti0.1O2 material was successfully synthesized by a conventional solid-state reaction method. The material delivered a superior specific capacity of 163 mAh g1 at 0.1C within the potential range from 1.5 to 4 V. The capacity and the coulombic efficiency of the material remained of 90% and 97% after 50 cycles of charge/discharge at a rate of 0.1C. The material also exhibited an excellent rate capability, with a discharge capacity of over 100 mAh.g−1 remained at a rate of 1.0C. The observed results suggested that Na1.0Li0.2Mn0.7Ti0.1O2 is a promising cathode material for sodium ion batteries.

ZnO nanoparticles embedded in graphene xerogel as anode materials in Zn/Ni batteries with superior electrochemical performances

In order to enhance practical applications of Zn/Ni batteries as rechargeable batteries, it is critical to increase their cycling stability. Herein, ZnO nanoparticles are embedded in xerogel of reduced graphene oxide to form ZnO/reduced graphene oxide composites via a simple one-step hydrothermal treatment. As anode in Zn/Ni batteries, the as-prepared ZnO/reduced graphene oxide composites exhibit high specific capacity (~ 580 mAh·g−1 at 6.5 Ag−1) and excellent cycling stability (stable within 1700 cycles). The introduction of reduced graphene oxide xerogel in the composites is found to immensely improve the electron transfer and long-term cycling stability of the composites. The as-prepared composites are extremely promising as anode in Zn/Ni batteries considering their facile preparation and superb electrochemical performance.