Grapevine-like high entropy oxide composites boost high-performance lithium sulfur batteries as bifunctional interlayers

Lithium-sulfur batteries(LSBs)with high energy densities have been demonstrated the potential for energy-intensive demand applications.However,their commercial applicability is hampered by hysteretic electrode reaction kinetics and the shuttle effect of lithium polysulfides(LiPSs).In this work,an interlayer consisting of high-entropy metal oxide(Cu_(0.7)Fe_(0.6)Mn_(0.4)Ni_(0.6)Sn_(0.5))O_(4) grown on carbon nanofibers(HEO/CNFs)is designed for LSBs.The CNFs with highly porous networks provide transport pathways for Li^(+) and e^(-),as well as a physical sieve effect to limit LiPSs crossover.In particular,the grapevine-like HEO nanoparticles generate metal-sulfur bonds with LiPSs,efficiently anchoring active materials.The unique structure and function of the interlayer enable the LSBs with superior electrochemical performance,i.e.,the high specific capacity of 1381 mAh g^(-1) at 0.1 C and 561 mAh g^(-1) at 6 C.This work presents a facile strategy for exploiting high-performance LSBs.

A Perspective on Energy Densities of Rechargeable Li-S Batteries and Alternative Sulfur-Based Cathode Materials

Lithium-ion battery has reached its capacity and energy density limits.In the past decade,significant efforts have been taken to explore new electrode materials that have the potential to enable high-energy-density battery systems.Among them,elemental sulfur is one of the high-capacity cathode candidates and has been studied intensively over the past decade.The formation of lithium polysulfides in ethereal liquid electrolyte upon cycling results in several challenges such as active material dissolution,shuttle effect,and limited cycle life.Although some approaches have been developed to overcome these issues,the attainable energy densities of lithium–sulfur(Li-S)batteries seem to be low.The main reason is largely due to the high electrolyte/sulfur(E/S)ratios used in the sulfur cathode.This perspective provides new insights on the energy density analysis of sulfur cathode.The“average mass density”of sulfur cathode is found to be a useful parameter for this purpose.Some emerging alternative sulfur-based cathode materials such as organopolysulfides and metal polysulfides which possess unique properties and performances are presented.They are promising to overcome the intrinsic issues associated with elemental sulfur cathode and enable truly high-energy-density Li-S battery systems.

Nitrogen-rich azoles as trifunctional electrolyte additives for high-performance lithium-sulfur battery

Rechargeable lithium-sulfur(Li-S)batteries are considered one of the most promising energy storage techniques owing to the high theoretical energy density.However,challenges still remain such as the shuttle effect of lithium polysulfides(LPSs)and the instability of lithium metal anode.Herein,we propose to use nitrogen-rich azoles,i.e.,triazole(Ta)and tetrazole(Tta),as trifunctional electrolyte additives for Li-S batteries.The azoles afford strong lithiophilicity for the chemisorption of LPSs.The density functional theory and experimental analysis verify the presence of Li bonds between the azoles and LPSs.The azoles can also interact with lithium salt in the electrolyte,leading to increase ionic conductivity and lithiumion transference number.Moreover,the azoles render particle-like lithium deposition on the lithium metal anode,leading to superlong cycling of a Li symmetric cell.The Li-S batteries with Ta and Tta exhibit the initial discharge capacity of 1425.5 and 1322.2 m Ah g^(-1),respectively,at 0.2 C rate,and promising cycling stability.They also enable enhanced cycling performance of a Li-organosulfide battery.

二次电池研究进展

能源的存储和利用是当今科学和技术发展中的重大课题之一,尤其是作为高效的电能/化学能转化装置的二次电池相关技术一直是科学家研究的热点领域。在此背景下,本文较为系统地介绍目前二次电池的重要研究进展,将从二次电池的发展历史引入,再到其相关的基础理论知识的介绍。随后较为详细地讨论当前不同体系的二次电池及相关应的关键材料的研究进展,涉及到锂离子电池、钠离子电池、钾离子电池、镁离子电池、锌离子电池、钙离子电池、铝离子电池、氟离子电池、氯离子电池、双离子电池、锂-硫(硒)电池、钠-硫(硒)电池、钾-硫(硒)电池、多价金属-硫基电池、锂-氧电池、钠-氧电池、钾-氧电池、多价金属-氧气电池、锂-溴(碘)电池、水系金属离子电池、光辅助电池、柔性电池、有机电池、金属-二氧化碳电池等。此外,也介绍了电池研究中常见的电极反应过程表征技术,包括冷冻电镜、透射电镜、同步辐射、原位谱学表征、磁性表征等。本文将有助于研究人员对二次电池进行全面系统的了解与把握,并为之后二次电池的研究提供很好的指导作用。

Regulating dissolution chemistry of nitrates in carbonate electrolyte for high-stable lithium metal batteries

Lithium metal batteries(LMBs)have received increasing attention due to the high energy density.However,the practical application of LMBs is limited due to the incompatibility of ester electrolytes.Transition metal(TM)nitrates have been reported as effective additives in ester electrolyte to improve the stability of lithium anode.Unfortunately,the nitrates are restricted to use due to their poor solubility.We find that the nitrates containing crystal water have high solubility in ester electrolytes.Considering that most TM nitrates contain crystal water and the crystal water can be used as a perfect solubilizer of nitrates,thus,the method is of universality and facile without introducing any solubilizing agent.Herein,In(NO_(3))_(3.6)H_(2)O is chosen as one typical case with increased solubility up to 0.2 M compared with In(NO_(3))_(3)which hardly dissolves in ester electrolyte.The additive promotes the rapid and stable formation of the solid electrolyte interface(SEI),which effectively inhibits the lithium dendrites formation.Moreover,the induced cathode electrolyte interface(CEI)maintains the structural stability of Li Ni_(0.8)Co_(0.1)Mn_(0.1)O_(2)(NCM811).As a result,the electrochemical performance of Li|NCM811 cell is obviously improved.Our study provides a new idea for dissolving nitrates in ester electrolytes and discloses the synergistic function of TM-ions.

Advances of entropy-stabilized homologous compounds for electrochemical energy storage

Recently, high-entropy materials(HEMs) have gained increasing interest in the field of energy storage technology on account of their unique structural characteristics and possibilities for tailoring functional properties. Herein, the development of this class of materials for electrochemical energy storage have been reviewed, especially the fundamental understanding of entropy-dominated phase-stabilization effects and prospective applications are presented. Subsequently, critical comments of HEMs on the different aspects of battery and supercapacitor are summarized with the underlying principles for the observed properties. In addition, we also summarize their potential advantages and remaining challenges, which will ideally provide some general guidelines and principles for researchers to study and develop advanced HEMs. The diversity of material design contributed by the entropy-mediated concept provides the researchers numerous ideas of new candidates for practical applications and ensures further research in the emerging field of energy storage.

Benzoselenol as an organic electrolyte additive in Li-S battery

Lithium-sulfur(Li-S)battery is one of the promising high-energy battery systems for future use.However,the shuttle effect due to the dissolved lithium polysulfides in ether electrolyte hampers its practical application.Applying electrolyte additives in Li-S battery has been widely acknowledged as an effective way to reduce the shuttle effect and improve cycling efficiency.In this work,benzoselenol(PhSeH)is used as an organic electrolyte additive in Li-S battery.It reacts with elemental sulfur to form phenyl selenosulfide,altering the redox pathway of the cathode with the regeneration of S8 at the end of charge and enabling new redox reactions with high reversibility.The Li-S coin cell with an optimized amount of PhSeH in the electrolyte delivers a high discharge capacity of 1,436 mAh·g^(−1)and a capacity retention of 92.86%in 200 cycles,and exhibits lower discharge overpotential in comparison to the cell with blank electrolyte.The Li-S pouch cell with a low electrolyte/sulfur(E/S)ratio of 4.0μL·mg^(−1)shows a discharge capacity of 1,398 mAh and excellent capacity retention for 20 cycles.

Chlorine-induced mixed valence of CuO_(x)/C to promote the electroreduction of carbon dioxide to ethylene

Electrochemical conversion of CO_(2)(CO_(2)RR)into high-value fuel is identified as one of the promising approaches to achieve carbon neutrality.The synthesis of high-efficiency CO_(2)reduction electrocatalysts with high C_(2):C_(1) selectivity remains a field of intense interest.Previous studies have shown that the presence of Cu(I)is beneficial for the reduction of CO_(2)into C_(2)products.However,the stable presence of Cu(I)remains controversial,especially in the negative potential window.Here we report a simple and easily scalable catalyst precursor Cu_(2)(OH)_(3)Cl/C,which automatically forms in-situ chlorine-doped Cu/Cu_(2)O heterointerface during electrocatalysis.The catalyst not only exhibits a Faradaic efficiency of 33.03%but also provides a long-term stability of Cu^(+),gaining a stable electrolysis of 11 h,with an ethylene/methane ratio over 50.The experimental results and mechanistic studies confirm that the presence of Cl^(-)inhibits the reduction of Cu^(+),inducing the formation of Cu^(0)/Cu^(+),and reduces the reaction energy of the intermediate ^(*)CO dimerization,thereby facilitating the formation of C_(2)products.This work provides a feasible way to synthesize copper ions with long-term and stable positive charge in CO_(2)RR and expands a new way to synthesize ethylene industrial products in the future.

Organopolysulfides as high-performance cathode materials for rechargeable aluminum-ion batteries

The development of aluminum-ion batteries(AIBs)is significantly confined by the limited high-performance cathode materials.Herein,organopolysulfides are investigated as active cathode materials to fabricate AIBs.A liquid-phase phenyl tetrasulfide(PTS)can deliver a capacity above 600 mAh g−1 after activation,with the maintenance of 253 mAh g−1 after 100 cycles.Owing to the different S locations,PTS shows several voltage plateaus and an average voltage of∼0.7 V vs.Al3+/Al with no decay upon cycling.More importantly,the liquid PTS can serve as a high-Coulombic-efficiency cathode(∼99.88%±0.57%after stabilization),enlighting the design of high-efficiency and low-resistance conversion-type cathode materials for AIBs.By experimental characterizations accompanied by theoretical calculations,it is found that PTS undergoes stepwise reaction procedures during discharge with final products of Al2S3 and AlCl2-coordinated phenyl sulfide,and partially reforms with elemental S and other organopolysulfides during charge.This study demonstrates new opportunities for the design of high-efficiency conversion-type cathode materials for advanced AIBs.

Nitrate additives for lithium batteries:Mechanisms,applications,and prospects

Lithium-metal batteries(LMBs)are considered as one of the most promising energy storage devices due to the high energy density and low reduction potential of the Li-metal anode.However,the growth of lithium dendrites results in accumulated dead Li and safety issues,limiting the practical application of LMBs.LiNO_(3)is a well-known additive in lithium-sulfur batteries to regulate the solid-electrolyte interphase(SEI),effectively suppressing the redox shuttle of polysulfides.Recently,other nitrates have been investigated in various electrolyte and battery systems,yielding improved SEI stability and cycling performance.In this review,we provide an overview of various nitrates,including LiNO_(3)for lithium batteries,focusing on their mechanisms and performance.We first discuss the effect of nitrate anions on SEI formation,as well as the cathode-electrolyte interphase(CEI).The solvation behavior regulated by nitrates is also extensively explored.Some strategies to improve the solubility of LiNO_(3)in ester-based electrolytes are then summarized,followed by a discussion of recent progress in the application of nitrates in different systems.Finally,further research directions are presented,along with challenges.This review provides a comprehensive understanding of nitrates and affords new and interesting ideas for the design of better electrolytes and battery systems.