Advancement of technology towards high-performance non-aqueous aluminum-ion batteries

Al-ion batteries(AIBs) have been identified as one of the most hopeful energy storage systems after Li-ion batteries on account for the ultrahigh volumetric capacity,high safety and low cost from the rich abundance of Al.Nonetheless,some inevitable shortcomings,such as the formation of passive oxide film,hydrogen side reactions and anode corrosion,finally limit the large-scale application of aqueous AIBs.The nonaqueous AIBs have been considered as one of most hopeful alternatives for high-powered electrochemical energy storage devices.Nonetheless,various technical and scientific obstacles should be resolved because nonaqueous AIBs are still nascent.Some significant efforts have aimed to resolve these issues towards large-scale applications,and some important advancement has been made.In the present review,we mainly intended to offer an overview of non-aqueous AIBs systems,and we comprehensively reviewed the recent research advancement of the cathode materials,anode materials electrolyte and collectors as well as the fundamental understanding of the functional mechanisms.In addition,we have also analyzed several technical challenges and summarized the strategies used for overcoming the challenges in improving the electrochemical properties,including morphology control,surface engineering,doping and construction of composite electrodes as well as the charge storage mechanisms of the materials with different crystal structures.At last,future research orientation and development prospect of the AIBs are proposed.

Towards high-performance anodes:Design and construction of cobalt-based sulfide materials for sodium-ion batteries

Sodium-ion batteries are increasingly becoming important in the energy storage field owing to their low cost and high natural abundance of sodium.Cobalt-based sulfide materials have been extensively studied as anode materials owing to their remarkable Na storage capability.Nevertheless,the application of cobalt-based sulfides is hampered by their serious capacity degradation and unsatisfactory cycling stability due to severe structural changes during cycling.Therefore,it is important to comprehensively summarize advances in the understanding and modification of cobalt-based sulfides from various perspectives.In the present review,recent advances on various cobalt-based sulfides,such as CoS,CoS_(2),Co_(3)S_(4),Co_(9)S_(8),NiCo_(2)S_(4),CUCo_(2)S_(4),and SnCoS_(4),are outlined with particular attention paid to strategies that improve their sodium storage performance.First,the mechanisms of charge storage are introduced.Subsequently,the key barriers to their extensive application and corresponding strategies for designing high-performance cobalt-based sulfide anode materials are discussed.Finally,key developments are summarized and future research directions are proposed based on recent advancements,aiming to offer possible fascinating strategies for the future promotion of cobalt-based sulfides as anode materials applied in sodium-ion batteries.

Porous spherical NiO@NiMoO4@PPy nanoarchitectures as advanced electrochemical pseudocapacitor materials

In this work, a rational design and construction of porous spherical Ni O@NiMoO4 wrapped with PPy was reported for the application of high-performance supercapacitor(SC). The results show that the NiMoO4 modification changes the morphology of Ni O, and the hollow internal morphology combined with porous outer shell of Ni O@NiMoO4 and Ni O@NiMoO4@PPy hybrids shows an increased specific surface area(SSA), and then promotes the transfer of ions and electrons. The shell of NiMoO4 and PPy with high electronic conductivity decreases the charge-transfer reaction resistance of Ni O, and then improves the electrochemical kinetics of Ni O. At 20 Ag^-1, the initial capacitances of Ni O, NiMoO4, Ni O@NiMoO4 and Ni O@NiMoO4@PPy are 456.0, 803.2, 764.4 and 941.6 Fg^-1, respectively. After 10,000 cycles, the corresponding capacitances are 346.8, 510.8, 641.2 and 904.8 Fg^-1, respectively. Especially, the initial capacitance of Ni O@NiMoO4@PPy is 850.2 Fg^-1, and remains 655.2 Fg^-1 with a high retention of 77.1% at30 Ag^-1 even after 30,000 cycles. The calculation result based on density function theory shows that the much stronger Mo-O bonds are crucial for stabilizing the Ni O@NiMoO4 composite, resulting in a good cycling stability of these materials.

Approaching high-performance electrode materials of ZnCo2S4 nanoparticle wrapped carbon nanotubes for supercapacitors

In this work,CNTs-wrapped ZnCo2S4 nanoparticle composites were constructed by a simple hydrothermal process.This process allows to wrap ZnCo2S4 nanoparticle in an interconnected CNT matrix that combines excellent electronic conductivity with good mechanical stability.The CNTs wrapping suppresses the aggregation of ZnCo2S4 nanoparticle,and assures an effective contact between electrolyte and ZnCo2S4 particles,then promotes rapid ion transportation.Specifically,ZnCo2S4@CNTs(5 wt%)composite shows the highest specific surface area,lowest polarization and the highest reversibility during cycling among all samples.ZnCo2S4@CNTs(0,2.5,5 and 10 wt%)electrodes deliver specific capacitances of 360.4,1012.8,1190.4 and 1015.6 F g^(-1) with capacitance retentions of 32.9%,81.3%,84.2%and 79.3%at 10 Ag^(-1) after 10,000 cycles.Even at higher current density of 30 A g^(-1),ZnCo2S4@CNTs(5 wt%)composite also delivers a specific capacitance of about 880 F g^(-1) with a capacitance retention of 93%after 30,000 cycles,revealing outstanding cycling stability.The above results exhibit that ZnCo2S4@CNTs composites can be promising candidates as electrode materials for pseudocapacitors with excellent electrochemical property in future applications.