Metal fluoride materials with high theoretical capacities are considered the next generation of Li-free conversion cathodes.However,the inherently sluggish reaction kinetics of metal fluorides result in unsatisfactory...Metal fluoride materials with high theoretical capacities are considered the next generation of Li-free conversion cathodes.However,the inherently sluggish reaction kinetics of metal fluorides result in unsatisfactory electrochemical performance.In this study,CoF_(2)was combined with carbonaceous materials to obtain graphitic carbon-encapsulated CoF_(2)nanoparticles uniformly embedded in an interconnected N-doped carbon matrix(CoF_(2)@NC),significantly boosting the inert kinetics and electronic conductivity.The CoF_(2)@NC nanocomposites exhibited a notable reversible capacity of 352.0 mAh·g^(-1)at 0.2 A·g^(-1).Notably,it maintained superior long-term cycling stability even at a high current density of 2 A·g^(-1),with a capacity of 235.5 mAh·g^(-1)after 1200 cycles,evidently exceeding that of commercially available CoF_(2)electrodes.Kinetic analysis indicated that the enhanced electrochemical performance originated from the increased contribution of capacitive effects.Furthermore,in-situ electrochemical impedance spectroscopy(EIS)results verify that the improved cycling performance is associated with the enhanced interfacial stability of CoF_(2)@NC.This research not only proposes a solution for the challenges of conversion cathodes in lithium-ion batteries,but also offers novel synthesis strategies for designing high-energy metal fluoride materials.展开更多
Transition metal sulfides are emerging as promising electrode materials for energy storage and conversion.In this work,hierarchical FeS2/C nanospheres are synthesized through a controllable solvothermal method followe...Transition metal sulfides are emerging as promising electrode materials for energy storage and conversion.In this work,hierarchical FeS2/C nanospheres are synthesized through a controllable solvothermal method followed by the annealing process.Spherical FeS2 core is homogeneously coated by thin carbon shell.The hierarchical nanostructure and carbon coating can enhance electron transfer and accommodate the stress originated from the volume change as well as suppress the shuttle effect of polysulfide.Consequently,as the cathode material of lithium ion batteries(LIBs),the FeS2/C nanospheres exhibit high reversible capacity of 676 m Ahg^-1 and excellent cycling life with the capacity retention of 97.1%after100 cycles.In addition,even at the high current density of 1.8 C,a reversible capacity of 437 m Ahg^-1 is obtained for the FeS2/C nanospheres,demonstrating its great prospect for practical applications in highperformance LIBs.展开更多
Rechargeable aluminum batteries(RABs)are attractive cadidates for next-generation energy storage and conversion,due to the low cost and high safety of Al resources,and high capacity of metal Al based on the three-elec...Rechargeable aluminum batteries(RABs)are attractive cadidates for next-generation energy storage and conversion,due to the low cost and high safety of Al resources,and high capacity of metal Al based on the three-electrons reaction mechanism.However,the development of RABs is greatly limited,because of the lack of advanced cathode materials,and their complicated and unclear reaction mechanisms.Exploring the novel nanostructured transition metal and carbon composites is an effective route for obtaining ideal cathode materials.In this work,we synthesize porous CoSnO_(3)/C nanocubes with oxygen vacancies for utilizing as cathodes in RABs for the first time.The intrinsic structure stability of the mixed metal cations and carbon coating can improve the cycling performance of cathodes by regulating the internal strains of the electrodes during volume expansion.The nanocubes with porous structures contribute to fast mass transportation which improves the rate capability.In addition to this,abundant oxygen vacancies promote the adsorption affinity of cathodes,which improves storage capacity.As a result,the CoSnO_(3)/C cathodes display an excellent reversible capacity of 292.1 mAh g^(-1) at 0.1 A g^(-1),a good rate performance with 109 mAh g^(-1) that is maintained even at 1 A g^(-1) and the provided stable cycling behavior for 500 cycles.Besides,a mechanism of intercalation of Al^(3+)within CoSnO_(3)/C cathode is proposed for the electrochemical process.Overall,this work provides a step toward the development of advanced cathode materials for RABs by engineering novel nanostructured mixed transition-metal oxides with carbon composite and proposes novel insights into chemistry for RABs.展开更多
Owing to the utilization of lithium metal as anode with the ultrahigh theoretical capacity density of 3860 mA h g^(-1)and oxide-based ceramic solid-state electrolytes(SE),e.g.,garnet-type Li7La_(3)Zr_(2)O_(12)(LLZO),a...Owing to the utilization of lithium metal as anode with the ultrahigh theoretical capacity density of 3860 mA h g^(-1)and oxide-based ceramic solid-state electrolytes(SE),e.g.,garnet-type Li7La_(3)Zr_(2)O_(12)(LLZO),all-state-state lithium metal batteries(ASLMBs)have been widely accepted as the promising alternatives for providing the satisfactory energy density and safety.However,its applications are still challenged by plenty of technical and scientific issues.In this contribution,the co-sintering temperature at 500℃is proved as a compromise method to fabricate the composite cathode with structural integrity and declined capacity fading of LiNi_(0.5)Co_(0.2)Mn_(0.3)O_(2)(NCM).On the other hand,it tends to form weaker grain boundary(GB)inside polycrystalline LLZO at inadequate sintering temperature for LLZO,which can induce the intergranular failure of SE during the growth of Li filament inside the unavoidable defect on the interface of SE.Therefore,increasing the strength of GB,refining the grain to 0.4μm,and precluding the interfacial defect are suggested to postpone the electro-chemo-mechanical failure of SE with weak GB.Moreover,the advanced sintering techniques to lower the co-sintering temperature for both NCM-LLZO composite cathode and LLZO SE can be posted out to realize the viability of state-of-the-art ASLMBs with higher energy density as well as the guaranteed safety.展开更多
To advance the application of layered oxide cathodes in fast-charging sodium-ion batteries,it is crucial to not only suppress irreversible phase transitions but also improve the rate capability of cathode materials an...To advance the application of layered oxide cathodes in fast-charging sodium-ion batteries,it is crucial to not only suppress irreversible phase transitions but also improve the rate capability of cathode materials and optimize Na^(+)diffusion kinetics to ensure high capacity output at various charge-discharge rates.In this research,the targeted F-substitution with a heavy ratio in oxygen anion layer optimizes the Na^(+)diffusion path and electronic conductivity of the material,thereby decreasing the Na^(+)diffusion barrier and imparting high-rate performance.At a 20 C rate,the cathode achieves a capacity of over 80 mAh g^(-1)with stable cycling performance.Additionally,the dual rivet effect between the transition metal layer and oxygen layer prevents significant phase transitions during charge/discharge within the 2-4.2 V range for the modified cathode.As a result,the F-substituted oxygen anion layer improved Na^(+)diffusion,electronic conductivity,and crystal plane structure stability,which led to the development of a highperformance,fast-charging sodium-ion battery(SIB),opening new avenues for commercial applications.展开更多
LiNi0.8Co0.1Mn0.1O2 cathode was synthesized using transition metal acetates under different synthesis conditions. Simultaneous thermogravimetric–differential scanning calorimetry–derivative thermogravimetric analysi...LiNi0.8Co0.1Mn0.1O2 cathode was synthesized using transition metal acetates under different synthesis conditions. Simultaneous thermogravimetric–differential scanning calorimetry–derivative thermogravimetric analysis was applied to investigating the mixture of transition metal acetates. X-ray powder diffraction and charge–discharge test were adopted to characterize the as-prepared LiNi0.8Co0.1Mn0.1O2. The mixture of transition metal acetates undergoes dehydration and decomposition during heating. All the examined LiNi0.8Co0.1Mn0.1O2 samples have a layered structure with R3 m space group. LiNi0.8Co0.1Mn0.1O2 samples prepared with different lithium sources under different synthesis conditions exhibit very different charge–discharge performances. The sample synthesized via the procedure of sintering at 800 °C after heating lithium carbonate and transition metal acetates at 550 °C achieves a highest capacity of 200.8 m A·h/g and an average capacity of 188.1 mA ·h/g in the first 20 cycles at 0.2C.展开更多
Long-life energy storage batteries are integral to energy storage systems and electric vehicles,with lithium-ion batteries(LIBs)currently being the preferred option for extended usage-life energy storage.To further ex...Long-life energy storage batteries are integral to energy storage systems and electric vehicles,with lithium-ion batteries(LIBs)currently being the preferred option for extended usage-life energy storage.To further extend the life span of LIBs,it is essential to intensify investments in battery design,manufacturing processes,and the advancement of ancillary materials.The pursuit of long durability introduces new challenges for battery energy density.The advent of electrode material offers effective support in enhancing the battery’s long-duration performance.Often underestimated as part of the cathode composition,the binder plays a pivotal role in the longevity and electrochemical performance of the electrode.Maintaining the mechanical integrity of the electrode through judicious binder design is a fundamental requirement for achieving consistent long-life cycles and high energy density.This paper primarily concentrates on the commonly employed cathode systems in lithium-ion batteries,elucidates the significance of binders for both,discusses the application status,strengths,and weaknesses of novel binders,and ultimately puts forth corresponding optimization strategies.It underscores the critical function of binders in enhancing battery performance and advancing the sustainable development of lithium-ion batteries,aiming to offer fresh insights and perspectives for the design of high-performance LIBs.展开更多
The outstanding performance of O3-type NaNi_(1/3)Fe_(1/3)Mn_(1/3)O_(2)(NFM111)at both high and low temperatures coupled with its impressive specific capacity makes it an excellent cathode material for sodium-ion batte...The outstanding performance of O3-type NaNi_(1/3)Fe_(1/3)Mn_(1/3)O_(2)(NFM111)at both high and low temperatures coupled with its impressive specific capacity makes it an excellent cathode material for sodium-ion batteries.However,its poor cycling,owing to highpressure phase transitions,is one of its disadvantages.In this study,Cu/Ti was introduced into NFM111 cathode material using a solidphase method.Through both theoretically and experimentally,this study found that Cu doping provides a higher redox potential in NFM111,improving its reversible capacity and charge compensation process.The introduction of Ti would enhance the cycling stability of the material,smooth its charge and discharge curves,and suppress its high-voltage phase transitions.Accordingly,the NaNi_(0.27)Fe_(0.28)Mn_(0.33)Cu_(0.05)Ti_(0.06)O_(2)sample used in the study exhibited a remarkable rate performance of 142.97 mAh·g^(-1)at 0.1 C(2.0-4.2 V)and an excellent capacity retention of 72.81%after 300 cycles at 1C(1C=150 mA·g^(-1)).展开更多
Carbon-based air cathodes offer low cost,high electrical conductivity,and structural tunability.However,they suffer from limited catalytic activity and inefficient gas transport,and they typically rely on noble metal ...Carbon-based air cathodes offer low cost,high electrical conductivity,and structural tunability.However,they suffer from limited catalytic activity and inefficient gas transport,and they typically rely on noble metal additives or complex multilayer configurations.To tackle these issues,this study devised a self-activated integrated carbon-based air cathode.By integrating in situ catalytic site construction with structural optimization,the strategy not only induces the formation of oxygen functional groups(─C─OH,─C═O,─COOH),hierarchical pores,and uniformly distributed active sites,but also establishes a favorable electronic and mass-transport environment.Furthermore,the roll-pressing-based integrated design streamlines electrode construction,reinforces interfacial bonding,and significantly enhances mechanical stability.Density functional theory(DFT)calculations show that oxygen functional groups initiate hydrogen bonding interaction and promote charge enrichment,which improves the activity of the cathode and facilitates intermediate adsorption/desorption in oxygen reduction and evolution reactions processes.As a result,the integrated air cathode-based rechargeable zinc-air batteries(RZABs)achieve a high specific capacity of 811 mAh g^(-1).It also performs well in quasi-solid-state RZABs and silicon-air batteries systems across a wide temperature range,demonstrating strong adaptability and application potential.This study provides a scalable and cost-effective design strategy for high-performance carbon-based air cathodes,offering new insights into advancing durable and practical metal-air energy systems.展开更多
Dual ion batteries(DIBs) exhibit broad application prospects in the field of electrical energy storage(EES)devices with excellent properties,such as high voltage,high energy density,and low cost.In the graphitebased D...Dual ion batteries(DIBs) exhibit broad application prospects in the field of electrical energy storage(EES)devices with excellent properties,such as high voltage,high energy density,and low cost.In the graphitebased DIBs,high voltage is needed to store enough anions with the formation of anion intercalation compound XCn(X=AlCl4-,PF6-,TFSI-,etc.).Hence,it is difficult for graphite-based DIBs to match proper anodes and electrolytes.Here,an Se/graphene composite is prepared via a convenient method,and assembled into a dual-ion full battery(DIFB) as anode with graphite cathode and 1 mol/L NaPF6 in EC:EMC(1:1,v:v).This DIFB has achieved a high discharge capacity of 75.9 mAh/g and high medium output voltage of 3.5 V at 0.1 A/g.Actually,the suitable anode materials,such as the present Se/graphene composite,are extremely important for the development and application of graphite-based DIBs.This study is enlightening for the design of future low-cost EES devices including graphite-based DIBs.展开更多
Aqueous zinc-ion batteries(ZIBs)are receiving a continuously increasing attention for mobile devices,especially for the flexible and wearable electronics,due to their non-toxicity,non-flammability,and low-cost feature...Aqueous zinc-ion batteries(ZIBs)are receiving a continuously increasing attention for mobile devices,especially for the flexible and wearable electronics,due to their non-toxicity,non-flammability,and low-cost features.Despite the significant progress in achieving higher capacities for electrode materials of ZIBs,to endow them with high flexibility and economic feasibility is,however,still a significant challenge remaining unsolved.Herein,we present a highly flexible composite film composed of carbon nanotube film and V_(2)O_(5)(CNTF@V_(2)O_(5))with high strength and high conductivity,which is prepared by simply impregnating a porous CNT film with an aqueous V_(2)O_(5)sol under vacuum.For this material,intimate incorporation between V_(2)O_(5)and CNTs has been achieved,successfully integrating the high zinc ion storage capability with high mechanical flexibility.As a result,this CNTF@V_(2)O_(5)film delivers a high capacity of 356.6 m Ah g^(-1)at 0.4 A g^(-1)and excellent cycling stability with 80.1%capacity retention after 500 cycles at 2.0 A g^(-1).The novel strategy and the outstanding battery performance presented in this work should shed light on the development of high-performance and flexible ZIBs.展开更多
Lithium-ion batteries(LIBs) as energy storage devices play an important role in all aspects of our life. The increasing energy demand of the society requires LIBs with higher energy density and better performance. We ...Lithium-ion batteries(LIBs) as energy storage devices play an important role in all aspects of our life. The increasing energy demand of the society requires LIBs with higher energy density and better performance. We here develop a new and easy-to-scaleup sol-gel method to coat a surface protection layer on commercial LiCoO2cathode. We demonstrate that a proper thickness can improve the cycling life with a higher cut-off potential(4.5 V), larger energy capacity(180 mAh/g at 0.5 C) and better energy density(35% more compared to non-coated LiCoO2). The mechanism of the protection layer is also revealed by a combination of electron microscopy and synchrotron X-ray spectroscopy.展开更多
Hierarchically-porous carbon nano sheets were prepared as a conductive additive for sulfur/polyacrylonitrile(S/PAN)composite cathodes using a simple heat treatment.In this study,kombucha(that was derived from symbioti...Hierarchically-porous carbon nano sheets were prepared as a conductive additive for sulfur/polyacrylonitrile(S/PAN)composite cathodes using a simple heat treatment.In this study,kombucha(that was derived from symbiotic culture of bacteria and yeast)carbon(KC)and graphene oxide(GO)were used as a carbon host matrix.These rational-designed S/PAN/KC/GO hybrid composites greatly suppress the diffusion of polysulfides by providing strong physical and chemical adsorption.The cathode delivered an initial discharge capacity of 1652 mAh·g^-1 at a 0.1 C rate and a 100th cycle capacity of 1193 mAh·g^-1.The nano sheets with embedded hierarchical pores create a conductive network that provide effective electron transfer and fast electrochemical kinetics.Further,the nitrogen component of PAN can raise the affinity/interaction of the carbon host with lithium polysulfides,supporting the cyclic performance.The results exploit the cumulative contribution of both the conductive carbon matrix and PAN in the enhanced performance of the positive electrode.展开更多
Layered Li-rich Mn-based oxides are promising cathode materials for Li-ion batteries due to their high capacity and high operation voltage.However,their commercial applications are hindered by irreversible capacity lo...Layered Li-rich Mn-based oxides are promising cathode materials for Li-ion batteries due to their high capacity and high operation voltage.However,their commercial applications are hindered by irreversible capacity loss in the first charge-discharge process,voltage decay during cycling,inefficient cyclability and rate capability.Many attempts have been performed to solve such issues,including the mechanism study and strategies to improve the electrochemical performance.This article provides a brief review and future perspective on the main challenges of the high-capacity Li-rich Mn-based cathodes for Li-ion batteries.展开更多
Flexible aqueous zinc-ion batteries(AZIBs)with air-recharging capability are a promising self-powered system applied in future wearable electronics.It is desired to develop high-capacity air-rechargeable AZIBs.Herein,...Flexible aqueous zinc-ion batteries(AZIBs)with air-recharging capability are a promising self-powered system applied in future wearable electronics.It is desired to develop high-capacity air-rechargeable AZIBs.Herein,we developed a flexible AZIB with air-recharging capability based on trinitrohexaazatrinaphthylene(TNHATN)cathode and a ZnSO_(4)electrolyte.The flexible Zn//TNHATN battery exhibits high volumetric energy density(21.36 mWh/cm^3)and excellent mechanical flexibility.Impressing,the discharged flexible Zn//TNHATN battery can be chemical self-charged via the redox reaction between TNHATN cathode and O_(2)from the air.After oxidation in air for 15 h,such flexible Zn//TNHATN battery can deliver a high specific capacity of 320 mAh/g at 0.5 A/g,displaying excellent air-recharging capability.Notably,this flexible Zn//TNHATN battery also works well in chemical or/and galvanostatic charging mixed modes,showing reusability.This work provides a new insight for designing flexible aqueous self-powered systems.展开更多
Oxocarbons(C_(n)O_(n),n=3,4,5,6,...)are a series of compounds that are only composed of carbonyl groups.The highly electrophilic carbon atoms in C_(n)O_(n)make their poor stability toward H_(2)O,and thus the synthesis...Oxocarbons(C_(n)O_(n),n=3,4,5,6,...)are a series of compounds that are only composed of carbonyl groups.The highly electrophilic carbon atoms in C_(n)O_(n)make their poor stability toward H_(2)O,and thus the synthesis of C_(n)O_(n)is very challenging.Here an oxidation-dehydration method is developed to successfully synthesize C_(4)O_(4)and C_(5)O_(5).The combination of nuclear magnetic resonance(^(13)C NMR,^(1)H NMR),mass spectra,and infrared spectra unambiguously proves the exact chemical structure of C_(4)O_(4)and C_(5)O_(5).When used as a cathode material in lithium-ion batteries(LIBs),C_(5)O_(5)could deliver a high discharge capacity of 698m Ah g-1(corresponding to an energy density of 1,256 Wh kg-1C_(5)O_(5)).Furthermore,ex-situ infrared spectra and density functional theory(DFT)calculations demonstrate that the carbonyl groups are redox active sites during discharge and charge processes.This work paves the way to achieve the synthesis and battery application of oxocarbons.展开更多
Hard carbon(HC)is widely used in sodium-ion batteries(SIBs),but its performance has always been limited by lowinitial Coulombic efficiency(ICE)and cycling stability.Cathode compensation agent is a favorable strategy t...Hard carbon(HC)is widely used in sodium-ion batteries(SIBs),but its performance has always been limited by lowinitial Coulombic efficiency(ICE)and cycling stability.Cathode compensation agent is a favorable strategy to make up for the loss of active sodium ions consumed byHCanode.Yet it lacks agent that effectively decomposes to increase the active sodium ions as well as regulate carbon defects for decreasing the irreversible sodium ions consumption.Here,we propose 1,2-dihydroxybenzene Na salt(NaDB)as a cathode compensation agent with high specific capacity(347.9 mAh g^(-1)),lower desodiation potential(2.4–2.8 V)and high utilization(99%).Meanwhile,its byproduct could functionalize HC with more C=O groups and promote its reversible capacity.Consequently,the presodiation hard carbon(pHC)anode exhibits highly reversible capacity of 204.7 mAh g^(-1) with 98%retention at 5 C rate over 1000 cycles.Moreover,with 5 wt%NaDB initially coated on the Na3V2(PO4)3(NVP)cathode,the capacity retention of NVP + NaDB|HC cell could increase from 22%to 89%after 1000 cycles at 1 C rate.This work provides a new avenue to improve reversible capacity and cycling performance of SIBs through designing functional cathode compensation agent.展开更多
Solid oxide electrolysis cells(SOECs)can effectively convert CO_(2)into high value-added CO fuel.In this paper,Sc-doped Sr_(2)Fe_(1.5)Mo_(0.3)Sc_(0.2)O_(6−δ)(SFMSc)perovskite oxide material is synthesized via solid-p...Solid oxide electrolysis cells(SOECs)can effectively convert CO_(2)into high value-added CO fuel.In this paper,Sc-doped Sr_(2)Fe_(1.5)Mo_(0.3)Sc_(0.2)O_(6−δ)(SFMSc)perovskite oxide material is synthesized via solid-phase method as the cathode for CO_(2)electrolysis by SOECs.XRD confirms that SFMSc exhibits a stable cubic phase crystal structure.The experimental results of TPD,TG,EPR,CO_(2)-TPD further demonstrate that Sc-doping increases the concentration of oxygen vacancy in the material and the chemical adsorption capacity of CO_(2)molecules.Electrochemical tests reveal that SFMSc single cell achieves a current density of 2.26 A/cm^(2) and a lower polarization impedance of 0.32Ω·cm^(2) at 800°C under the applied voltage of 1.8 V.And no significant performance attenuation or carbon deposition is observed after 80 h continuous long-term stability test.This study provides a favorable support for the development of SOEC cathode materials with good electro-catalytic performance and stability.展开更多
Na_(3)V_(2)(PO_(4))_(3)(NVP)has garnered great attentions as a prospective cathode material for sodium-ion batteries(SIBs)by virtue of its decent theoretical capacity,superior ion conductivity and high structural stab...Na_(3)V_(2)(PO_(4))_(3)(NVP)has garnered great attentions as a prospective cathode material for sodium-ion batteries(SIBs)by virtue of its decent theoretical capacity,superior ion conductivity and high structural stability.However,the inherently poor electronic conductivity and sluggish sodium-ion diffusion kinetics of NVP material give rise to inferior rate performance and unsatisfactory energy density,which strictly confine its further application in SIBs.Thus,it is of significance to boost the sodium storage performance of NVP cathode material.Up to now,many methods have been developed to optimize the electrochemical performance of NVP cathode material.In this review,the latest advances in optimization strategies for improving the electrochemical performance of NVP cathode material are well summarized and discussed,including carbon coating or modification,foreign-ion doping or substitution and nanostructure and morphology design.The foreign-ion doping or substitution is highlighted,involving Na,V,and PO_(4)^(3−)sites,which include single-site doping,multiple-site doping,single-ion doping,multiple-ion doping and so on.Furthermore,the challenges and prospects of high-performance NVP cathode material are also put forward.It is believed that this review can provide a useful reference for designing and developing high-performance NVP cathode material toward the large-scale application in SIBs.展开更多
The growing need for higher energy density in rechargeable batteries necessitates the exploration of cathode materials with enhanced specific energy for lithium-ion batteries.Due to their exceptional cost-effectivenes...The growing need for higher energy density in rechargeable batteries necessitates the exploration of cathode materials with enhanced specific energy for lithium-ion batteries.Due to their exceptional cost-effectiveness and specific capacity,lithium-rich manganese-based cathode materials(LRMs)obtain in-creasing attention in the pursuit of enhancing energy density and reducing costs.The implementation has faced obstacles in various applications due to substantial capacity and voltage degradation,insufficient safety performance,and restricted rate capability during cycling.These issues arise from the migration of transition metal,the release of oxygen,and structural transformation.In this review,we provide an integrated survey of the structure,lithium storage mechanism,challenges,and origins of LRMs,as well as recent advancements in various coating strategies.Particularly,the significance of optimizing the design of the cathode electrolyte interphase was emphasized to enhance electrode performance.Furthermore,future perspective was also addressed alongside in-situ measurements,advanced synthesis techniques,and the application of machine learning to overcome encountered challenges in LRMs.展开更多
基金supported by the National Natural Science Foundation of China(Nos.22279101,22172117 and 52072298)Foshan Science and Technology Innovation Team Project(No.1920001004098)+1 种基金Scientific Research Program Funded by Education Department of Shaanxi Provincial Government(No.22JP056)the Natural Science Basic Research Program of Shaanxi(No.2024JC-YBQN-0141).
文摘Metal fluoride materials with high theoretical capacities are considered the next generation of Li-free conversion cathodes.However,the inherently sluggish reaction kinetics of metal fluorides result in unsatisfactory electrochemical performance.In this study,CoF_(2)was combined with carbonaceous materials to obtain graphitic carbon-encapsulated CoF_(2)nanoparticles uniformly embedded in an interconnected N-doped carbon matrix(CoF_(2)@NC),significantly boosting the inert kinetics and electronic conductivity.The CoF_(2)@NC nanocomposites exhibited a notable reversible capacity of 352.0 mAh·g^(-1)at 0.2 A·g^(-1).Notably,it maintained superior long-term cycling stability even at a high current density of 2 A·g^(-1),with a capacity of 235.5 mAh·g^(-1)after 1200 cycles,evidently exceeding that of commercially available CoF_(2)electrodes.Kinetic analysis indicated that the enhanced electrochemical performance originated from the increased contribution of capacitive effects.Furthermore,in-situ electrochemical impedance spectroscopy(EIS)results verify that the improved cycling performance is associated with the enhanced interfacial stability of CoF_(2)@NC.This research not only proposes a solution for the challenges of conversion cathodes in lithium-ion batteries,but also offers novel synthesis strategies for designing high-energy metal fluoride materials.
基金funded by the Natural Science Foundation of Zhejiang Provincial (No. LQ17E020003)the National Natural Science Foundation of China (No. 51804092)
文摘Transition metal sulfides are emerging as promising electrode materials for energy storage and conversion.In this work,hierarchical FeS2/C nanospheres are synthesized through a controllable solvothermal method followed by the annealing process.Spherical FeS2 core is homogeneously coated by thin carbon shell.The hierarchical nanostructure and carbon coating can enhance electron transfer and accommodate the stress originated from the volume change as well as suppress the shuttle effect of polysulfide.Consequently,as the cathode material of lithium ion batteries(LIBs),the FeS2/C nanospheres exhibit high reversible capacity of 676 m Ahg^-1 and excellent cycling life with the capacity retention of 97.1%after100 cycles.In addition,even at the high current density of 1.8 C,a reversible capacity of 437 m Ahg^-1 is obtained for the FeS2/C nanospheres,demonstrating its great prospect for practical applications in highperformance LIBs.
基金supported by the National Natural Science Foundation of China (Grant No.22075028).
文摘Rechargeable aluminum batteries(RABs)are attractive cadidates for next-generation energy storage and conversion,due to the low cost and high safety of Al resources,and high capacity of metal Al based on the three-electrons reaction mechanism.However,the development of RABs is greatly limited,because of the lack of advanced cathode materials,and their complicated and unclear reaction mechanisms.Exploring the novel nanostructured transition metal and carbon composites is an effective route for obtaining ideal cathode materials.In this work,we synthesize porous CoSnO_(3)/C nanocubes with oxygen vacancies for utilizing as cathodes in RABs for the first time.The intrinsic structure stability of the mixed metal cations and carbon coating can improve the cycling performance of cathodes by regulating the internal strains of the electrodes during volume expansion.The nanocubes with porous structures contribute to fast mass transportation which improves the rate capability.In addition to this,abundant oxygen vacancies promote the adsorption affinity of cathodes,which improves storage capacity.As a result,the CoSnO_(3)/C cathodes display an excellent reversible capacity of 292.1 mAh g^(-1) at 0.1 A g^(-1),a good rate performance with 109 mAh g^(-1) that is maintained even at 1 A g^(-1) and the provided stable cycling behavior for 500 cycles.Besides,a mechanism of intercalation of Al^(3+)within CoSnO_(3)/C cathode is proposed for the electrochemical process.Overall,this work provides a step toward the development of advanced cathode materials for RABs by engineering novel nanostructured mixed transition-metal oxides with carbon composite and proposes novel insights into chemistry for RABs.
基金the National Natural Science Foundation of China(12102328)for supporting this work。
文摘Owing to the utilization of lithium metal as anode with the ultrahigh theoretical capacity density of 3860 mA h g^(-1)and oxide-based ceramic solid-state electrolytes(SE),e.g.,garnet-type Li7La_(3)Zr_(2)O_(12)(LLZO),all-state-state lithium metal batteries(ASLMBs)have been widely accepted as the promising alternatives for providing the satisfactory energy density and safety.However,its applications are still challenged by plenty of technical and scientific issues.In this contribution,the co-sintering temperature at 500℃is proved as a compromise method to fabricate the composite cathode with structural integrity and declined capacity fading of LiNi_(0.5)Co_(0.2)Mn_(0.3)O_(2)(NCM).On the other hand,it tends to form weaker grain boundary(GB)inside polycrystalline LLZO at inadequate sintering temperature for LLZO,which can induce the intergranular failure of SE during the growth of Li filament inside the unavoidable defect on the interface of SE.Therefore,increasing the strength of GB,refining the grain to 0.4μm,and precluding the interfacial defect are suggested to postpone the electro-chemo-mechanical failure of SE with weak GB.Moreover,the advanced sintering techniques to lower the co-sintering temperature for both NCM-LLZO composite cathode and LLZO SE can be posted out to realize the viability of state-of-the-art ASLMBs with higher energy density as well as the guaranteed safety.
基金supported by the National Natural Science Foundation of China(Nos.22178221,22208221)the Shenzhen Science and Technology Program(Nos.JCYJ20220818095805012,JCYJ20230808105109019)+2 种基金the Natural Science Foundation of Guangdong Province(Nos.2024A1515011078,2024A1515011507)the Scientific Foundation for Youth Scholars of Shenzhen University(868-000001032522,827-0001004)the Instrumental Analysis Center of Shenzhen University for the assistance with the Electron Microscope technical support。
文摘To advance the application of layered oxide cathodes in fast-charging sodium-ion batteries,it is crucial to not only suppress irreversible phase transitions but also improve the rate capability of cathode materials and optimize Na^(+)diffusion kinetics to ensure high capacity output at various charge-discharge rates.In this research,the targeted F-substitution with a heavy ratio in oxygen anion layer optimizes the Na^(+)diffusion path and electronic conductivity of the material,thereby decreasing the Na^(+)diffusion barrier and imparting high-rate performance.At a 20 C rate,the cathode achieves a capacity of over 80 mAh g^(-1)with stable cycling performance.Additionally,the dual rivet effect between the transition metal layer and oxygen layer prevents significant phase transitions during charge/discharge within the 2-4.2 V range for the modified cathode.As a result,the F-substituted oxygen anion layer improved Na^(+)diffusion,electronic conductivity,and crystal plane structure stability,which led to the development of a highperformance,fast-charging sodium-ion battery(SIB),opening new avenues for commercial applications.
基金Project(2010ZC051)supported by the Natural Science Foundation of Yunnan Province,ChinaProject(20140439)supported by the Analysis and Testing Foundation from Kunming University of Science and Technology,ChinaProject(14118245)supported by the Starting Research Fund from Kunming University of Science and Technology,China
文摘LiNi0.8Co0.1Mn0.1O2 cathode was synthesized using transition metal acetates under different synthesis conditions. Simultaneous thermogravimetric–differential scanning calorimetry–derivative thermogravimetric analysis was applied to investigating the mixture of transition metal acetates. X-ray powder diffraction and charge–discharge test were adopted to characterize the as-prepared LiNi0.8Co0.1Mn0.1O2. The mixture of transition metal acetates undergoes dehydration and decomposition during heating. All the examined LiNi0.8Co0.1Mn0.1O2 samples have a layered structure with R3 m space group. LiNi0.8Co0.1Mn0.1O2 samples prepared with different lithium sources under different synthesis conditions exhibit very different charge–discharge performances. The sample synthesized via the procedure of sintering at 800 °C after heating lithium carbonate and transition metal acetates at 550 °C achieves a highest capacity of 200.8 m A·h/g and an average capacity of 188.1 mA ·h/g in the first 20 cycles at 0.2C.
基金We would like to show gratitude to the Yunnan Province Basic Research Major Project(202501BC070006(Y.Wang))Key Industry Science and Technology Projects for University Services in Yunnan Province(FWCY ZNT2024002(Y.Wang))+3 种基金National Natural Science Foundation of China(22279070(L.Wang))and(U21A20170(X.He))the Ministry of Science and Technology of China(2019YFA0705703(L.Wang))Beijing Natural Science Foundation(L242005(X.He))Key Industry Science and Technology Projects for University Services in Yunnan Province(FWCY BSPY2024011(T.Lai)).
文摘Long-life energy storage batteries are integral to energy storage systems and electric vehicles,with lithium-ion batteries(LIBs)currently being the preferred option for extended usage-life energy storage.To further extend the life span of LIBs,it is essential to intensify investments in battery design,manufacturing processes,and the advancement of ancillary materials.The pursuit of long durability introduces new challenges for battery energy density.The advent of electrode material offers effective support in enhancing the battery’s long-duration performance.Often underestimated as part of the cathode composition,the binder plays a pivotal role in the longevity and electrochemical performance of the electrode.Maintaining the mechanical integrity of the electrode through judicious binder design is a fundamental requirement for achieving consistent long-life cycles and high energy density.This paper primarily concentrates on the commonly employed cathode systems in lithium-ion batteries,elucidates the significance of binders for both,discusses the application status,strengths,and weaknesses of novel binders,and ultimately puts forth corresponding optimization strategies.It underscores the critical function of binders in enhancing battery performance and advancing the sustainable development of lithium-ion batteries,aiming to offer fresh insights and perspectives for the design of high-performance LIBs.
基金supported by the Low-Cost Long-Life Batteries program,China(No.WL-24-08-01)the National Natural Science Foundation of China(No.22279007)。
文摘The outstanding performance of O3-type NaNi_(1/3)Fe_(1/3)Mn_(1/3)O_(2)(NFM111)at both high and low temperatures coupled with its impressive specific capacity makes it an excellent cathode material for sodium-ion batteries.However,its poor cycling,owing to highpressure phase transitions,is one of its disadvantages.In this study,Cu/Ti was introduced into NFM111 cathode material using a solidphase method.Through both theoretically and experimentally,this study found that Cu doping provides a higher redox potential in NFM111,improving its reversible capacity and charge compensation process.The introduction of Ti would enhance the cycling stability of the material,smooth its charge and discharge curves,and suppress its high-voltage phase transitions.Accordingly,the NaNi_(0.27)Fe_(0.28)Mn_(0.33)Cu_(0.05)Ti_(0.06)O_(2)sample used in the study exhibited a remarkable rate performance of 142.97 mAh·g^(-1)at 0.1 C(2.0-4.2 V)and an excellent capacity retention of 72.81%after 300 cycles at 1C(1C=150 mA·g^(-1)).
基金funded by the National Nature Science Foundation of China(62264006,62574102)“Thousand Talents Program”of Yunnan Province for Young Talents,Innovative Research Teams(in Science and Technology)in the University of Yunnan Province(IRTSTYN),XingDian Talent Support Program for Young Talents,and Frontier Research Team of Kunming University 2023,The Basic Research Project of Yunnan Province(Nos.202201AU070022)+2 种基金Kunming University Talent Introduction Fund(Nos.YJL20024)Yunnan Province Education Department Scientific Research Fund Project(Nos.2024Y759)Undergraduate Innovation and Entrepreneurship Training Program Project of Yunnan Provincial(202411393005)。
文摘Carbon-based air cathodes offer low cost,high electrical conductivity,and structural tunability.However,they suffer from limited catalytic activity and inefficient gas transport,and they typically rely on noble metal additives or complex multilayer configurations.To tackle these issues,this study devised a self-activated integrated carbon-based air cathode.By integrating in situ catalytic site construction with structural optimization,the strategy not only induces the formation of oxygen functional groups(─C─OH,─C═O,─COOH),hierarchical pores,and uniformly distributed active sites,but also establishes a favorable electronic and mass-transport environment.Furthermore,the roll-pressing-based integrated design streamlines electrode construction,reinforces interfacial bonding,and significantly enhances mechanical stability.Density functional theory(DFT)calculations show that oxygen functional groups initiate hydrogen bonding interaction and promote charge enrichment,which improves the activity of the cathode and facilitates intermediate adsorption/desorption in oxygen reduction and evolution reactions processes.As a result,the integrated air cathode-based rechargeable zinc-air batteries(RZABs)achieve a high specific capacity of 811 mAh g^(-1).It also performs well in quasi-solid-state RZABs and silicon-air batteries systems across a wide temperature range,demonstrating strong adaptability and application potential.This study provides a scalable and cost-effective design strategy for high-performance carbon-based air cathodes,offering new insights into advancing durable and practical metal-air energy systems.
基金financial support by the National Natural Science Foundation of China(No.91963118)Fundamental Research Funds for the Central Universities(No.2412019ZD010)。
文摘Dual ion batteries(DIBs) exhibit broad application prospects in the field of electrical energy storage(EES)devices with excellent properties,such as high voltage,high energy density,and low cost.In the graphitebased DIBs,high voltage is needed to store enough anions with the formation of anion intercalation compound XCn(X=AlCl4-,PF6-,TFSI-,etc.).Hence,it is difficult for graphite-based DIBs to match proper anodes and electrolytes.Here,an Se/graphene composite is prepared via a convenient method,and assembled into a dual-ion full battery(DIFB) as anode with graphite cathode and 1 mol/L NaPF6 in EC:EMC(1:1,v:v).This DIFB has achieved a high discharge capacity of 75.9 mAh/g and high medium output voltage of 3.5 V at 0.1 A/g.Actually,the suitable anode materials,such as the present Se/graphene composite,are extremely important for the development and application of graphite-based DIBs.This study is enlightening for the design of future low-cost EES devices including graphite-based DIBs.
基金supported by the National Natural Science Foundation of China(No.51072130,51502045 and 21905202)the Australian Research Council(ARC)through Discovery Project(No.DP200100365)the Discovery Early Career Researcher Award(DECRA,No.DE170100871)program。
文摘Aqueous zinc-ion batteries(ZIBs)are receiving a continuously increasing attention for mobile devices,especially for the flexible and wearable electronics,due to their non-toxicity,non-flammability,and low-cost features.Despite the significant progress in achieving higher capacities for electrode materials of ZIBs,to endow them with high flexibility and economic feasibility is,however,still a significant challenge remaining unsolved.Herein,we present a highly flexible composite film composed of carbon nanotube film and V_(2)O_(5)(CNTF@V_(2)O_(5))with high strength and high conductivity,which is prepared by simply impregnating a porous CNT film with an aqueous V_(2)O_(5)sol under vacuum.For this material,intimate incorporation between V_(2)O_(5)and CNTs has been achieved,successfully integrating the high zinc ion storage capability with high mechanical flexibility.As a result,this CNTF@V_(2)O_(5)film delivers a high capacity of 356.6 m Ah g^(-1)at 0.4 A g^(-1)and excellent cycling stability with 80.1%capacity retention after 500 cycles at 2.0 A g^(-1).The novel strategy and the outstanding battery performance presented in this work should shed light on the development of high-performance and flexible ZIBs.
基金supported by Callahan Faculty Scholar Endowment Fund from Oregon State University,USA
文摘Lithium-ion batteries(LIBs) as energy storage devices play an important role in all aspects of our life. The increasing energy demand of the society requires LIBs with higher energy density and better performance. We here develop a new and easy-to-scaleup sol-gel method to coat a surface protection layer on commercial LiCoO2cathode. We demonstrate that a proper thickness can improve the cycling life with a higher cut-off potential(4.5 V), larger energy capacity(180 mAh/g at 0.5 C) and better energy density(35% more compared to non-coated LiCoO2). The mechanism of the protection layer is also revealed by a combination of electron microscopy and synchrotron X-ray spectroscopy.
基金All the authors from Alagappa University acknowledge the financial support by DST-SERB,New Delhi under the Physical sciences,grant sanctioned vide EMR/2016/006302
文摘Hierarchically-porous carbon nano sheets were prepared as a conductive additive for sulfur/polyacrylonitrile(S/PAN)composite cathodes using a simple heat treatment.In this study,kombucha(that was derived from symbiotic culture of bacteria and yeast)carbon(KC)and graphene oxide(GO)were used as a carbon host matrix.These rational-designed S/PAN/KC/GO hybrid composites greatly suppress the diffusion of polysulfides by providing strong physical and chemical adsorption.The cathode delivered an initial discharge capacity of 1652 mAh·g^-1 at a 0.1 C rate and a 100th cycle capacity of 1193 mAh·g^-1.The nano sheets with embedded hierarchical pores create a conductive network that provide effective electron transfer and fast electrochemical kinetics.Further,the nitrogen component of PAN can raise the affinity/interaction of the carbon host with lithium polysulfides,supporting the cyclic performance.The results exploit the cumulative contribution of both the conductive carbon matrix and PAN in the enhanced performance of the positive electrode.
基金This work was supported by NSFC(21621091)National Key Research and Development of China(2016YFB0100202)+4 种基金Natural Science Foundation of Fujian Province(2015J01063)the support of National Materials Genome Project(2016YFB0700600)National Key R&D Program of China(2016YFB0700600)the Guangdong Innovation Team Project(No.2013N080)Shenzhen Science and Technology Research(Nos.JCYJ20151015162256516,JCYJ20150729111733470 and JCYJ20160226105838578)。
文摘Layered Li-rich Mn-based oxides are promising cathode materials for Li-ion batteries due to their high capacity and high operation voltage.However,their commercial applications are hindered by irreversible capacity loss in the first charge-discharge process,voltage decay during cycling,inefficient cyclability and rate capability.Many attempts have been performed to solve such issues,including the mechanism study and strategies to improve the electrochemical performance.This article provides a brief review and future perspective on the main challenges of the high-capacity Li-rich Mn-based cathodes for Li-ion batteries.
基金supported by the National Natural Science Foundation of China(No.21975034)the Project Funded by the Priority Academic Program Development of Jiangsu Higher Education Institutionsthe Research Project of State Key Laboratory of Coordination Chemistry。
文摘Flexible aqueous zinc-ion batteries(AZIBs)with air-recharging capability are a promising self-powered system applied in future wearable electronics.It is desired to develop high-capacity air-rechargeable AZIBs.Herein,we developed a flexible AZIB with air-recharging capability based on trinitrohexaazatrinaphthylene(TNHATN)cathode and a ZnSO_(4)electrolyte.The flexible Zn//TNHATN battery exhibits high volumetric energy density(21.36 mWh/cm^3)and excellent mechanical flexibility.Impressing,the discharged flexible Zn//TNHATN battery can be chemical self-charged via the redox reaction between TNHATN cathode and O_(2)from the air.After oxidation in air for 15 h,such flexible Zn//TNHATN battery can deliver a high specific capacity of 320 mAh/g at 0.5 A/g,displaying excellent air-recharging capability.Notably,this flexible Zn//TNHATN battery also works well in chemical or/and galvanostatic charging mixed modes,showing reusability.This work provides a new insight for designing flexible aqueous self-powered systems.
基金supported by the National Key R&D Program of China(2022YFB2402200)the National Natural Science Foundation of China(21905143,22121005,22020102002,21835004)Frontiers Science Center for New Organic Matter of Nankai University(63181206)。
文摘Oxocarbons(C_(n)O_(n),n=3,4,5,6,...)are a series of compounds that are only composed of carbonyl groups.The highly electrophilic carbon atoms in C_(n)O_(n)make their poor stability toward H_(2)O,and thus the synthesis of C_(n)O_(n)is very challenging.Here an oxidation-dehydration method is developed to successfully synthesize C_(4)O_(4)and C_(5)O_(5).The combination of nuclear magnetic resonance(^(13)C NMR,^(1)H NMR),mass spectra,and infrared spectra unambiguously proves the exact chemical structure of C_(4)O_(4)and C_(5)O_(5).When used as a cathode material in lithium-ion batteries(LIBs),C_(5)O_(5)could deliver a high discharge capacity of 698m Ah g-1(corresponding to an energy density of 1,256 Wh kg-1C_(5)O_(5)).Furthermore,ex-situ infrared spectra and density functional theory(DFT)calculations demonstrate that the carbonyl groups are redox active sites during discharge and charge processes.This work paves the way to achieve the synthesis and battery application of oxocarbons.
基金supported by National Natural Science Foundation of China(No.22278308 and 22109114)Open Foundation of Shanghai Jiao Tong University Shaoxing Research Institute of Renewable Energy and Molecular Engineering(Grant number:JDSX2022023).
文摘Hard carbon(HC)is widely used in sodium-ion batteries(SIBs),but its performance has always been limited by lowinitial Coulombic efficiency(ICE)and cycling stability.Cathode compensation agent is a favorable strategy to make up for the loss of active sodium ions consumed byHCanode.Yet it lacks agent that effectively decomposes to increase the active sodium ions as well as regulate carbon defects for decreasing the irreversible sodium ions consumption.Here,we propose 1,2-dihydroxybenzene Na salt(NaDB)as a cathode compensation agent with high specific capacity(347.9 mAh g^(-1)),lower desodiation potential(2.4–2.8 V)and high utilization(99%).Meanwhile,its byproduct could functionalize HC with more C=O groups and promote its reversible capacity.Consequently,the presodiation hard carbon(pHC)anode exhibits highly reversible capacity of 204.7 mAh g^(-1) with 98%retention at 5 C rate over 1000 cycles.Moreover,with 5 wt%NaDB initially coated on the Na3V2(PO4)3(NVP)cathode,the capacity retention of NVP + NaDB|HC cell could increase from 22%to 89%after 1000 cycles at 1 C rate.This work provides a new avenue to improve reversible capacity and cycling performance of SIBs through designing functional cathode compensation agent.
基金supported by National Key R&D Program of China(2021YFB4001401)National Natural Science Foundation of China(52272190,22178023).
文摘Solid oxide electrolysis cells(SOECs)can effectively convert CO_(2)into high value-added CO fuel.In this paper,Sc-doped Sr_(2)Fe_(1.5)Mo_(0.3)Sc_(0.2)O_(6−δ)(SFMSc)perovskite oxide material is synthesized via solid-phase method as the cathode for CO_(2)electrolysis by SOECs.XRD confirms that SFMSc exhibits a stable cubic phase crystal structure.The experimental results of TPD,TG,EPR,CO_(2)-TPD further demonstrate that Sc-doping increases the concentration of oxygen vacancy in the material and the chemical adsorption capacity of CO_(2)molecules.Electrochemical tests reveal that SFMSc single cell achieves a current density of 2.26 A/cm^(2) and a lower polarization impedance of 0.32Ω·cm^(2) at 800°C under the applied voltage of 1.8 V.And no significant performance attenuation or carbon deposition is observed after 80 h continuous long-term stability test.This study provides a favorable support for the development of SOEC cathode materials with good electro-catalytic performance and stability.
基金partly supported by the National Natural Science Foundation of China(Grant No.52272225).
文摘Na_(3)V_(2)(PO_(4))_(3)(NVP)has garnered great attentions as a prospective cathode material for sodium-ion batteries(SIBs)by virtue of its decent theoretical capacity,superior ion conductivity and high structural stability.However,the inherently poor electronic conductivity and sluggish sodium-ion diffusion kinetics of NVP material give rise to inferior rate performance and unsatisfactory energy density,which strictly confine its further application in SIBs.Thus,it is of significance to boost the sodium storage performance of NVP cathode material.Up to now,many methods have been developed to optimize the electrochemical performance of NVP cathode material.In this review,the latest advances in optimization strategies for improving the electrochemical performance of NVP cathode material are well summarized and discussed,including carbon coating or modification,foreign-ion doping or substitution and nanostructure and morphology design.The foreign-ion doping or substitution is highlighted,involving Na,V,and PO_(4)^(3−)sites,which include single-site doping,multiple-site doping,single-ion doping,multiple-ion doping and so on.Furthermore,the challenges and prospects of high-performance NVP cathode material are also put forward.It is believed that this review can provide a useful reference for designing and developing high-performance NVP cathode material toward the large-scale application in SIBs.
基金the support from the National Natural Science Foun-dation of China(Grant No.U21A20311)the Distinguished Scientist Fellowship Program(DSFP)at King Saud University,Riyadh,Saudi Arabia.
文摘The growing need for higher energy density in rechargeable batteries necessitates the exploration of cathode materials with enhanced specific energy for lithium-ion batteries.Due to their exceptional cost-effectiveness and specific capacity,lithium-rich manganese-based cathode materials(LRMs)obtain in-creasing attention in the pursuit of enhancing energy density and reducing costs.The implementation has faced obstacles in various applications due to substantial capacity and voltage degradation,insufficient safety performance,and restricted rate capability during cycling.These issues arise from the migration of transition metal,the release of oxygen,and structural transformation.In this review,we provide an integrated survey of the structure,lithium storage mechanism,challenges,and origins of LRMs,as well as recent advancements in various coating strategies.Particularly,the significance of optimizing the design of the cathode electrolyte interphase was emphasized to enhance electrode performance.Furthermore,future perspective was also addressed alongside in-situ measurements,advanced synthesis techniques,and the application of machine learning to overcome encountered challenges in LRMs.
