High-Energy Lithium-Ion Batteries:Recent Progress and a Promising Future in Applications

It is of great significance to develop clean and new energy sources with high-efficient energy storage technologies,due to the excessive use of fossil energy that has caused severe environmental damage.There is great interest in exploring advanced rechargeable lithium batteries with desirable energy and power capabilities for applications in portable electronics,smart grids,and electric vehicles.In practice,high-capacity and low-cost electrode materials play an important role in sustaining the progresses in lithium-ion batteries.This review aims at giving an account of recent advances on the emerging high-capacity electrode materials and summarizing key barriers and corresponding strategies for the practical viability of these electrode materials.Effective approaches to enhance energy density of lithium-ion batteries are to increase the capacity of electrode materials and the output operation voltage.On account of major bottlenecks of the power lithium-ion battery,authors come up with the concept of integrated battery systems,which will be a promising future for high-energy lithium-ion batteries to improve energy density and alleviate anxiety of electric vehicles.

Quasi-Solid-State Ion-Conducting Arrays Composite Electrolytes with Fast Ion Transport Vertical-Aligned Interfaces for All-Weather Practical Lithium-Metal Batteries

The rapid improvement in the gel polymer electrolytes(GPEs)with high ionic conductivity brought it closer to practical applications in solid-state Li-metal batteries.The combination of solvent and polymer enables quasi-liquid fast ion transport in the GPEs.However,different ion transport capacity between solvent and polymer will cause local nonuniform Li+distribution,leading to severe dendrite growth.In addition,the poor thermal stability of the solvent also limits the operating-temperature window of the electrolytes.Optimizing the ion transport environment and enhancing the thermal stability are two major challenges that hinder the application of GPEs.Here,a strategy by introducing ion-conducting arrays(ICA)is created by vertical-aligned montmorillonite into GPE.Rapid ion transport on the ICA was demonstrated by 6Li solid-state nuclear magnetic resonance and synchrotron X-ray diffraction,combined with computer simulations to visualize the transport process.Compared with conventional randomly dispersed fillers,ICA provides continuous interfaces to regulate the ion transport environment and enhances the tolerance of GPEs to extreme temperatures.Therefore,GPE/ICA exhibits high room-temperature ionic conductivity(1.08 mS cm^(−1))and long-term stable Li deposition/stripping cycles(>1000 h).As a final proof,Li||GPE/ICA||LiFePO_(4) cells exhibit excellent cycle performance at wide temperature range(from 0 to 60°C),which shows a promising path toward all-weather practical solid-state batteries.

Bacterial Cellulose Composite Solid Polymer Electrolyte With High Tensile Strength and Lithium Dendrite Inhibition for Long Life Battery

The development of metallic lithium anode is restrained by lithium dendrite growth during cycling.The solid polymer electrolyte with high mechanical strength and lithium ion conductivity could be applied to inhibit lithium dendrite growth.To prepare the high-performance solid polymer electrolyte,the environment-friendly and cheap bacterial cellulose(BC)is used as filler incorporating with PEO-based electrolyte owing to good mechanical properties and Li salts compatibility.PEO/Li TFSI/BC composite solid polymer electrolytes(CSPE)are prepared easily by aqueous mixing in water.The lithium ion transference number of PEO/Li TFSI/BC CSPE is 0.57,which is higher than PEO/Li TFSI solid polymer electrolyte(SPE)(0.409).The PEO/Li TFSI/BC CSPE exhibits larger tensile strength(4.43 MPa)than PEO/Li TFSI SPE(1.34 MPa).The electrochemical window of composite electrolyte is widened 1.43 V by adding BC.Density functional theory calculations indicate that flex of PEO chains around Li atoms is suppressed,suggesting the enhanced lithium ion conductivity.Frontier molecular orbitals results suggest that an unfavorable intermolecular charge transfer lead to achieve higher potential for BC composite electrolyte.All solid-state Li metal battery with PEO/Li TFSI/BC CSPE delivers longer cycle life for 600 cycles than PEO/Li TFSI SPE battery(50 cycles).Li symmetrical battery using PEO/Li TFSI/BC CSPE could be stable for 1160 h.

The Design and Preparation of Multi-dimensional Nanostructured Materials and Electrochemical Energy Storage

Herein,we report some facile and general methods to directly grow metal oxide(TiO_2,SnO_2,NiO,Co_3O_4 and MCo_2O_4)nanosheets on0-dimensional sulfonated polystyrene spheres,one-dimensional CNTs,polymeric nanotubes or mesoporous carbon fibers and two-dimensional graphene oxide.After calcinations in air or inert atmosphere,these materials were converted into metal oxides hollow spheres assembled

减缓自由阴离子迁移以缓解浓差极化用于高性能的聚合物锂金属电池

Traditional dual-ion lithium salts have been widely used in solid polymer lithium-metal batteries(LMBs).Nevertheless, concentration polarization caused by uncontrolled migration of free anions has severely caused the growth of lithium dendrites. Although single-ion conductor polymers(SICP) have been developed to reduce concentration polarization, the poor ionic conductivity caused by low carrier concentration limits their application. Herein, a dual-salt quasi-solid polymer electrolyte(QSPE), containing the SICP network as a salt and traditional dual-ion lithium salt, is designed for retarding the movement of free anions and simultaneously providing sufficient effective carriers to alleviate concentration polarization. The dual salt network of this designed QSPE is prepared through in-situ crosslinking copolymerization of SICP monomer, regular ionic conductor, crosslinker with the presence of the dual-ion lithium salt,delivering a high lithium-ion transference number(0.75) and satisfactory ionic conductivity(1.16 × 10^(-3) S cm^(-1) at 30 ℃). Comprehensive characterizations combined with theoretical calculation demonstrate that polyanions from SICP exerts a potential repulsive effect on the transport of free anions to reduce concentration polarization inhibiting lithium dendrites. As a consequence, the Li||LiFePO_4 cell achieves a long-cycle stability for 2000 cycles and a 90% capacity retention at 30 ℃. This work provides a new perspective for reducing concentration polarization and simultaneously enabling enough lithiumions migration for high-performance polymer LMBs.

How the microenvironment dominated by the distance effect to regulate the FeN_(4)site ORR activity and selectivity?

The distance effect of the doped heteroatoms away from the catalytic centers has rarely been reported.In this work,we conducted density functional theory calculations to thoroughly investigate the influence of heteroatom(N,P,B,and S atoms)doping distance on the oxygen reduction reaction(ORR)activity of graphene-based FeN_(4)sites.We uncovered a Sabatier-like relationship between heteroatom doping distance and ORR activity of FeN_(4)sites.The nearest doping does not significantly improve and even block the ORR activity of FeN_(4)sites.Optimal ORR activity is achieved when the heteroatoms are 4-5Å(N,P,and S atoms)or 6-7Å(B atoms)away from the Fe atoms.Analysis of electronic structure indicates that distance effect can modulate the local chemical environment of Fe atoms,thereby account for the changes in ORR activity along with the doping distance and doping atoms.This study provides insights into the influence of heteroatom doping on the chemical environment of reaction active centers,and provides the theoretical guidance for controlling the doping distance of heteroatoms to achieve optimal catalytic activity and selectivity.

High loading cotton cellulose-based aerogel self-standing electrode for Li-S batteries

Lithium-sulfur(Li-S) batteries have attracted considerable attention due to their high energy density(2600 Wh kg-1). However, its commercialization is hindered seriously by the low loading and utilization rate of sulfur cathodes. Herein, we designed the cellulose-based graphene carbon composite aerogel(CCA) self-standing electrode to enhance the performance of Li-S batteries. The CCA contributes to the mass loading and utilization efficiency of sulfur, because of its unique physical structure: low density(0.018 g cm-3), large specific surface area(657.85 m2 g-1), high porosity(96%), and remarkable electrolyte adsorption(42.25 times). Compared to Al(about 49%), the CCA displayed excellent sulfur use efficiency(86%) and could reach to high area capacity of 8.60 mAh cm-2 with 9.11 mgS loading. Meanwhile,the CCA exhibits the excellent potential for pulse sensing applications due to its flexibility and superior sensitivity to electrical response signals.

Insights into Reduction of CO_(2)to CO Catalyzed by Pyramidal-4Ni Clusters Supported on Doped CeO_(2)

Converting CO_(2)into valuable chemicals has become a widely used research method for CO_(2)conversion.In this work,the catalytic performance of pyramidal-4Ni catalysts supported on rare earth metal-doped CeO_(2)towardCO_(2)reductionreaction(CO_(2)RR)was investigated by using density-functional theorycalculations.For rare earth metal-doped CeO_(2),2Ce is substituted by 2 trivalent cations and at the same time one oxygen vacancy is created to make charge compensation.We investigated the oxygen vacancy nearest(Vo,N)and next-nearest(Vo,NN)to 4Ni,and found releasing CO and CO_(2)dissociation are the rate-determining steps,respectively,via the path of Vo,N and Vo,NN.Among the studied dopants(Ga,Sb,Lu,Gd,Pr,La,Bi),Gd is identified as the best dopant for catalyzing the reduction of CO_(2)at 823 K,with the turn-over frequency(TOF)of 104 times as large as that over 4Ni supported on pure CeO_(2).This exploration provides theoretical support and guidance for the research and application of rare earth metaldoped CeO_(2)-loaded Ni catalysts in the field of CO_(2)reduction.

Nonflammable PVDF-based gel polymer electrolytes modified by dimethyl methylphosphate for wide temperature range,long cycle-life and high-safety lithium metal batteries

Gel polymer electrolytes(GPEs)has been considered as a promising candidate for the development of lithium metal batteries(LMBs)with high energy density and high safety,yet most reported GPEs is flammable,making the LMBs still facing great safety hazards.Herein,we used dimethyl methylphosphate(DMMP)as the functional flame retardant and plasticizer for poly(vinylidene fluoride)(PVDF)matrix to develop a novel nonflammable PVDF-DMMP GPEs for LMBs.The DMMP not only highly enhances the flame resistance of PVDF-DMMP GPEs,the efficient dissociation of lithium salt and the rapid transport of lithium ions,but also helps to form stable and robust CEI/SEI layers.As a result,the ultrathin PVDF-DMMP GPEs(∼20µm)present superb flame resistance,high ionic conductivity(1.34×10^(−3) S cm^(−1) at 30℃),fast lithium ion transport(t_(Li^(+))=0.59at 30℃),high electrochemical stability voltage window(over 4 V)at 30–80℃ and uniform lithium deposition.When used in Li∥Li symmetric cells,Li∥LiFePO_(4)(LFP)and Li∥LiNi_(0.8)Co_(0.1)Mn_(0.1)O_(2) full cells,the nonflammable PVDF-DMMP GPEs could endow these cells with long-term cycle stability,high rate capability,wide-temperature operation ranges(from−20 to 80℃)and high safety simultaneously.Even when suffering from harsh deconstructive tests,the Li∣PVDF-DMMP GPEs∣LFP pouch cells still work normally without any safety hazards.The actual energy density of the packed pouch cell is as high as 508 Wh kg^(−1).Therefore,our work can provide a promising strategy for the design of high safety and high-energy-density LMBs.

Periodic Defect Boundary-Mediated Activity of Electrocatalytic Oxygen Reduction Reactions of Fe-N-C Catalysts

The introduction of defects can adjust the activity of graphene-based single-atom catalysts for oxygen reduction reactions(ORR).Herein,we for the first time investigate the ORR catalytic activity of FeN_(4)sites embedded on graphene with four types of line-defective boundary via density functional theory calculations.Our results show that periodic line defects consisting of pentagon-pentagon-octagon(C_(585))or quad-octagon chains(C_(484))can significantly enhance ORR activity,owing to the optimized electronic structures of FeN_(4)sites.The spin magnetic moment and the valence state of the Fe atom are both well correlated with the ORR overpotential.Experimental investigations further corroborate that FeN_(4)with a high degree of defects exhibits better ORR activity and stability compared to FeN_(4)sites of pristine graphene and commercial Pt/C.This work unravels the influence of the periodic defect boundary on the ORR performance of Fe-N-C catalysts and paves the way towards the rational design of highly effective single-atom electrocatalysts.

Phase boundary engineering of metal-organic-framework-derived carbonaceous nickel selenides for sodium-ion batteries

Nano Research volume 13,pages2289–2298(2020)Cite this article 347 Accesses 1 Altmetric Metrics details Abstract Sodium-ion batteries(SIBs)are promising power sources due to the low cost and abundance of battery-grade sodium resources,while practical SIBs suffer from intrinsically sluggish diffusion kinetics and severe volume changes of electrode materials.Metal-organic framework(MOFs)derived carbonaceous metal compound offer promising applications in electrode materials due to their tailorable composition,nanostructure,chemical and physical properties.Here,we fabricated hierarchical MOF-derived carbonaceous nickel selenides with bi-phase composition for enhanced sodium storage capability.As MOF formation time increases,the pyrolyzed and selenized products gradually transform from a single-phase Ni3Se4 into bi-phase NiSex then single-phase NiSe2,with concomitant morphological evolution from solid spheres into hierarchical urchin-like yolk-shell structures.As SIBs anodes,bi-phase NiSex@C/CNT-10h(10 h of hydrothermal synthesis time)exhibits a high specific capacity of 387.1 mAh/g at 0.1 A/g,long cycling stability of 306.3 mAh/g at a moderately high current density of 1 A/g after 2,000 cycles.Computational simulation further proves the lattice mismatch at the phase boundary facilitates more interstitial space for sodium storage.Our understanding of the phase boundary engineering of transformed MOFs and their morphological evolution is conducive to fabricate novel composites/hybrids for applications in batteries,catalysis,sensors,and environmental remediation.

Ionic liquid assisted electrochemical coating zinc nanoparticles on carbon cloth as lithium dendrite suppressing host

The application of lithium metal anode with high specific capacity and energy density is limited by the volume expansion and pulverization caused by dendrite growth during cycle process.We propose a composite lithium anode by immersing molten lithium on the flexible three-dimensional(3D)carbon cloth scaffold with the zinc nanoparticles.The lithiophilic zinc nanoparticles layer of framework is synthesized by fast and easy electrochemical deposition from ionic liquid avoiding high temperature,high pressure and toxic reagent.The lithium is infused into the 3D lithiophilic framework,the composite anode is obtained.The steady network structure can confine the lithium and lead to Li dendrite restraining and reducing volume change due to the low interfacial resistance and reduce the effective current density,which induced the homogeneous Li growth.Benefiting from this,the Li infused 3D carbon cloth-Zn symmetric battery exhibits a low stripping/plating overpotential(~30 mV)and can be stable over 900 h at 1 mA cm-2.The Li//LiFePO4 battery delivers higher reversible capacity(140 mAh g^-1 at 2 C and 120 mAh g^-1 at 5 C)and stable cycling for 1500 and 2000 cycles than bare Li.

Highly Stretchable and Transparent Ionic Conductor with Novel Hydrophobicity and Extreme-Temperature Tolerance

Highly stretchable and transparent ionic conducting materials have enabled new concepts of electronic devices denoted as iontronics,with a distinguishable working mechanism and performances from the conventional electronics.However,the existing ionic conducting materials can hardly bear the humidity and temperature change of our daily life,which has greatly hindered the development and real-world application of iontronics.Herein,we design an ion gel possessing unique traits of hydrophobicity,humidity insensitivity,wide working temperature range(exceeding 100℃,and the range covered our daily life temperature),high conductivity(10^(-3)~10^(-5) S/cm),extensive stretchability,and high transparency,which is among the bestperforming ionic conductors ever developed for flexible iontronics.Several ion gel-based iontronics have been demonstrated,including large-deformation sensors,electroluminescent devices,and ionic cables,which can serve for a long time under harsh conditions.The designed material opens new potential for the real-world application progress of iontronics.

Tuning the local electronic structure of oxygen vacancies over copper-doped zinc oxide for efficient CO_(2) electroreduction

Oxygen vacancies in metal oxides can serve as electron trap centers to capture CO_(2) and lower energy barriers for the electrochemical CO_(2) reduction reaction(CO_(2)RR).Under aqueous electrolytes,however,such charge-enriched active sites can be occupied by adsorbed hydrogen(H∗)and lose their effectiveness for the CO_(2)RR.Here,we develop an efficient catalyst consisting of Cu-doped,defect-rich ZnO(Cu–ZnO)for the CO_(2)RR,which exhibits enhanced CO Faradaic efficiency and current density compared to pristine ZnO.The introduced Cu dopants simultaneously stabilize neighboring oxygen vacancies and modulate their local electronic structure,achieving inhibition of hydrogen evolution and acceleration of the CO_(2)RR.In a flow cell test,a current density of more than 45​mA​cm^(−2) and a CO Faradaic efficiency of>80%is obtained for a Cu–ZnO electrocatalyst in the wide potential range of−0.76​V to−1.06​V vs.Reversible Hydrogen Electrode(RHE).This work opens up great opportunities for dopant-modulated metal oxide catalysts for the CO_(2)RR.

Highly aligned lithiophilic electrospun nanofiber membrane for the multiscale suppression of Li dendrite growth

Using inorganic fibrous membranes as protective layers has yielded success in suppressing dendrite growth.However,conventional fibrous membranes usually have large voids and low affinity for Li,promoting inhomogeneous charge distribution and allowing some dendrites to grow.Herein,we introduce a highly aligned TiO_(2)/SiO_(2)(A-TS)electrospun nanofiber membrane as a protective layer for the Li metal anode.The A-TS membrane is fabricated by a custom-made electrospinning system with an automatic fiber alignment collector that allows control of the fibers’orientation.At the scale of the individual fibers,their high binding energies with Li can attract more“dead”Li by reacting with the SiO_(2) component of the composite,avoiding uncontrollable deposition on the metal anode.At the membrane scale,these highly ordered structures achieve homogeneous contact and charge distribution on the Li metal surface,leaving no vulnerable areas to nucleate dendrite formation.Additionally,the excellent mechanical and thermal stability properties of the A-TS membrane prevent any potential puncturing by dendrites or thermal runaway in a battery.Hence,an A-TS@Li anode exhibits stable cycling performance when used in both Li-S and Li-NCM811 batteries,highlighting significant reference values for the future design and development of high-energy-density metal-based battery systems.

Direct integration of ultralow-platinum alloy into nanocarbon architectures for efficient oxygen reduction in fuel cells

Developing efficient platinum(Pt)-based electrocatalysts is enormously significant for fuel cells.Herein,we report an integrated electrocatalyst of ultralow-Pt alloy encapsulated into nitrogen-doped nanocarbon architecture for efficient oxygen reduction reaction.This hybrid Pt-based catalyst achieves a mass activity of 3.46 A mg^(-1)_(pt)the potential of 0.9 V vs.RHE with a negligible stability decay after 10,000 cycles.More importantly,this half-cell activity can be expressed at full cell level with a high Pt utilization of 10.22 W mg^(-1)_(Pt cathode)and remarkable durability after 30,000 cycles in single-cell.Experimental and theoretical investigations reveal that a highly strained Pt structure with an optimal Pt-0 binding energy is induced by the incorporation of Co/Ni into Pt lattice,which would account for the improved reaction kinetics.The synergistic catalysis due to nitrogen-doped nanocarbon architecture and active Pt component is responsible for the enhanced catalytic activity.Meanwhile,the strong metal-support interaction and optimized hydrophilic properties of nanocarbon matrix facilitate efficient mass transport and water management.This work may provide significant insights in designing the low-Pt integrated electrocatalysts for fuel cells and beyond.