Unfolding the structural features of NASICON materials for sodium-ion full cells

Sodium-ion batteries(SIBs)are potential candidates for the replacement of lithium-ion batteries to meet the increasing demands of electrical storage systems due to the low cost and high abundance of sodium.Sodium superionic conductor(NASICON)structured materials have attracted enormous interest in recent years as electrode materials for safer and long-term performance of SIBs for electric energy storage smart grids.These materials have a threedimensional robust framework,high redox potential,thermal stability,and a fast Na^(+)-ion diffusion mechanism.However,NASICON has low intrinsic electronic conductivity,which limits the electrochemical performance.This review describes the structural features of NASICONs to illustrate the ion storage mechanism and electrochemical performance of SIBs.Details of the NASICON crystal structure,the affiliated Na^(+)-ion diffusion mechanism,morphology,and electrochemical performance of these materials in sodiumion half-cells as well as full cells are described.In addition to the application as electrode materials,the use of NASICONs as solid electrolytes is also elaborated in solid-state SIBs.Based on these aspects,we have provided more perspectives in terms of the commercialization of SIBs and strategies to overcome the limitations of NASICONs.Hence,this review is expected to provide the researchers of energy storage with an in-depth understanding of NASICON materials with the knowledge of structural features,which will provide a new avenue on the practicality of SIBs.

Exploring the thermal stability of lithium-ion cells via accelerating rate calorimetry:A review

Given the importance of lithium-ion cell safety,a comprehensive review on the thermal stability of lithium-ion cells investigated by accelerating rate calorimetry(ARC),is provided in the present work.The operating mechanism of ARC is discussed first,including the usage and the reaction kinetics.Besides that,the thermal stability of the cathode/anode materials at elevated temperatures is revealed by examining the impacts of some significant factors,i.e.,the lithium content,particle size,material density,lithium salt,solvent,additive,binder and initial heating temperature.A comparison of the common cathode materials indicates that the presence of Mn and polyanion could significantly enhance the thermal stability of cathode materials,while the doping of Al also helps to restrain the reactivity.Except for their high capacity,some alloy materials demonstrate more competitive safety than traditional carbon anode materials.Furthermore,the thermal behaviors of full cells under abusive conditions are reviewed here.Due to the sensitivity of ARC to the kinetic parameters,a reaction kinetic modeling can be built on the basis of ARC profiles,to predict the thermal behaviors of cell components and cells.Herein,a shortcircuit modeling is exampled.

Wire-in-Wire TiO_(2)/C Nanofibers Free-Standing Anodes for Li-Ion and K-Ion Batteries with Long Cycling Stability and High Capacity

Wearable and portable mobile phones play a critical role in the market, and one of the key technologies is the flexible electrode with high specific capacity and excellent mechanical flexibility. Herein, a wire-in-wire TiO_(2)/C nanofibers (TiO_(2) ww/CN) film is synthesized via electrospinning with selenium as a structural inducer. The interconnected carbon network and unique wire- in-wire nanostructure cannot only improve electronic conductivity and induce effective charge transports, but also bring a superior mechanic flexibility. Ulti-mately, TiO_(2) ww/CN film shows outstanding electrochemical performance as free-standing electrodes in Li/K ion batteries. It shows a discharge capacity as high as 303 mAh g^(−1) at 5 A g^(−1) after 6000 cycles in Li half-cells, and the unique structure is well-reserved after long-term cycling. Moreover, even TiO_(2) has a large diffusion barrier of K^(+), TiO_(2) ww/CN film demonstrates excellent perfor-mance (259 mAh g^(−1) at 0.05 A g^(−1) after 1000 cycles) in K half-cells owing to extraordinary pseudocapacitive contribution. The Li/K full cells consisted of TiO_(2) ww/CN film anode and LiFePO_(4)/Perylene-3,4,9,10-tetracarboxylic dianhydride cathode possess outstanding cycling stability and demonstrate practical application from lighting at least 19 LEDs. It is, therefore, expected that this material will find broad applications in portable and wearable Li/K-ion batteries.

A Mixed Ether Electrolyte for Lithium Metal Anode Protection in Working Lithium-Sulfur Batteries

Lithium-sulfur(Li-S) battery is considered as a promising energy storage system to realize high energy density.Nevertheless,unstable lithium metal anode emerges as the bottleneck toward practical applications,especially with limited anode excess required in a working full cell.In this contribution,a mixed diisopropyl ether-based(mixed-DIPE) electrolyte was proposed to effectively protect lithium metal anode in Li-S batteries with sulfurized polyacrylonitrile(SPAN) cathodes.The mixed-DIPE electrolyte improves the compatibility to lithium metal and suppresses the dissolution of lithium polysulfides,rendering significantly improved cycling stability.Concretely,Li | Cu half-cells with the mixed-DIPE electrolyte cycled stably for 120 cycles,which is nearly five times longer than that with routine carbonate-based electrolyte.Moreover,the mixedDIPE electrolyte contributed to a doubled life span of 156 cycles at 0.5 C in Li | SPAN full cells with ultrathin 50 μm Li metal anodes compared with the routine electrolyte.This contribution affords an effective electrolyte formula for Li metal anode protection and is expected to propel the practical applications of high-energy-density Li-S batteries.

Combined cold,heat and power(CCHP)systems and fuel cells for CCHP applications:a topological review

As the basis for the study,this manuscript was written at a time when the energy crisis is affecting most parts of the world and most es-pecially the prevailing and rampant electricity crisis in most developing countries.As a result,50 combined cooling,heating and power(CCHP)systems studies were reviewed,which included the internal combustion engine(ICE),Stirling engine,biomass,micro turbine,solar and biogas,photovoltaic(PV)and gas turbine,wind turbine,PV and micro-turbine,solid-oxide and phosphoric-acid fuel cells(FCs),ICE and thermoelectric generator,low-temperature(LT)polymer electrolyte membrane(PEM),inlet air throttling gas turbine,ground source heat pump(GSHP)micro gas turbine and PV,ICE and GSHP,ICE with dehumidification and refrigeration,5-kW PEM FC,thermoelectric cooler and LT-PEM FC,Stirling engine and molten carbonate FC,thermo-acoustic organic Rankine cycle,solar-thermal,geothermal,integrated energy systems,power-and heat-storage systems,energy-conversion systems,thermodynamic and thermo-economic optimization strategies,working fluids based on hydrogen,helium as well as ammonia,H_(2)O,CO_(2) etc.Of these reviewed CCHP systems,FC-based CCHP systems were of the greatest interest,particularly the PEM FC.Consequently,FCs were further investigated,whereby the seven popular types of FCs identified and classified were summarily compared with each other,from which the PEM FC was preferred due to its practical popularity.However,PEM FCs,like all FCs,are susceptible to the fuel-starvation phenomenon;therefore,six FC-assisted schemes were examined,from which the FC assisted with the supercapacitor and battery technique was the most widely applied.In sum,the significance of the study entails assorted CCHP systems,FCs,their highlights,their applications and their pros and cons in a single reference document that anyone can easily use to holistically understand the characteristics of the CCHP systems.The study concludes with our perspective,by which we formulate and propose an alternative innovative unique CCHP system model under research,which is based exclusively on green tech-nologies:FCs,lithium-ion battery,ultracapacitor,thermoelectricity and an energy-management system using MATLAB■.

High-performance lithium-ion batteries based on polymer/graphene hybrid cathode material

Organic and carbon-based lithium-ion batteries possess abundant resources,nontoxicity,environmental friendliness,and high performance,and they have been widely studied in the past decades.However,it remains a challenge to construct such batteries with high capacity,high cycling stability,and high conductivity simultaneously.Here,we elaborately design and integrate organic polymer(p-FcPZ) with graphene network to create a hybrid material(p-FcPZ@G) for high-performance lithium-ion batteries(LIBs).The bi-polar polymer p-FcPZ containing multiple redox-active sites endows p-FcPZ@G with both remarkable cycling stability and high capacity.The porous conductive graphene network with a large surface area facilitates rapid ions/electrons transportation,resulting in superior rate performance.Therefore,the half-cell based on p-FcPZ@G cathode exhibits simultaneously high capacity(~250 mA h g^(-1) at 50 mA g^(-1)),excellent cycling stability(retention of 99.999% per cycle for 10,000 cycles at 2,000 mA g^(-1)) and superior rate performance.Additionally,the graphene-based full cell assembled with p-FcPZ@G cathode and graphene anode also demonstrates comprehensively high electrochemical performance.