Higher nickel content endows Ni-rich cathode materials LiNi_(x)Co_yMn_(1-x-y)O_(2)(x>0.6)with higher specific capacity and high energy density,which is regarded as the most promising cathode materials for Li-ion ba...Higher nickel content endows Ni-rich cathode materials LiNi_(x)Co_yMn_(1-x-y)O_(2)(x>0.6)with higher specific capacity and high energy density,which is regarded as the most promising cathode materials for Li-ion batteries.However,the deterioration of structural stability hinders its practical application,especially under harsh working conditions such as high-temperature cycling.Given these circumstances,it becomes particularly critical to clarify the impact of the crystal morphology on the structure and high-temperature performance as for the ultrahigh-nickel cathodes.Herein,we conducted a comprehensive comparison in terms of microstructure,high-temperature long-cycle phase evolution,and high-temperature electrochemical stability,revealing the differences and the working mechanisms among polycrystalline(PC),single-crystalline(SC)and Al doped SC ultrahigh-nickel materials.The results show that the PC sample suffers a severe irreversible phase transition along with the appearance of microcracks,resulting a serious decay of both average voltage and the energy density.While the Al doped SC sample exhibits superior cycling stability with intact layered structure.In-situ XRD and intraparticle structural evolution characterization reveal that Al doping can significantly alleviate the irreversible phase transition,thus inhibiting microcracks generation and enabling enhanced structure.Specifically,it exhibits excellent cycling performance in pouch-type full-cell with a high capacity retention of 91.8%after 500 cycles at 55℃.This work promotes the fundamental understanding on the correlation between the crystalline morphology and high-temperature electrochemical stability and provides a guide for optimization the Ni-rich cathode materials.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
Along with the extensive application of energy storage devices,the spent lithium-ion batteries(LIBs)are unquestionably classified into the secondary resources due to its high content of several valuable metals.However...Along with the extensive application of energy storage devices,the spent lithium-ion batteries(LIBs)are unquestionably classified into the secondary resources due to its high content of several valuable metals.However,current recycling methods have the main drawback to their tedious process,especially the purification and separation process.Herein,we propose a simplified process to recycle both cathode(LiCoO_(2))and anode(graphite)in the spent LIBs and regenerate newly high-performance anode material,CoO/CoFe2O4/expanded graphite(EG).This process not only has the advantages of succinct procedure and easy control of reaction conditions,but also effectively separates and recycles lithium from transition metals.The 98.43%of lithium is recovered from leachate when the solid product CoO/CoFe2O4/EG is synthesized as anode material for LIBs.And the product exhibits improved cyclic stability(890 mAh g^(-1) at 1 A g^(-1) after 700 cycles)and superior rate capability(208 mAh g^(-1) at 5 A g^(-1)).The merit of this delicate recycling design can be summarized as three aspects:the utilization of Fe impurity in waste LiCoO_(2),the transformation of waste graphite to EG,and the regeneration of anode material.This approach properly recycles the valuable components of spent LIBs,which introduces an insight into the future recycling.展开更多
In this paper,the ammonia leaching process and high-energy ball milling method were adapted to recover spent LiCoO_(2) material.The ammonia reduction leaching mechanism of LiCoO_(2) material in the ammonia-sodium sulf...In this paper,the ammonia leaching process and high-energy ball milling method were adapted to recover spent LiCoO_(2) material.The ammonia reduction leaching mechanism of LiCoO_(2) material in the ammonia-sodium sulfite-ammonium chloride system was elucidated.Compared with untreated LiCoO_(2) material,the leaching equilibrium time of LiCoO_(2) after ball-milled for 5 h was reduced from 48 h to 4 h,and the leaching efficiency of lithium and cobalt was improved from 69.86%and 70.80%to 89.86%and98.22%,respectively.Importantly,the apparent activation energy and leaching kinetic equation of the reaction was calculated by the shrinking core reaction model,indicating that the reaction was controlled by the chemical reaction.展开更多
In this paper, we investigate how to compute the minimum distance between a point and a parametric surface, and then to return the nearest point (foot point) on the surface as well as its corresponding parameter, whic...In this paper, we investigate how to compute the minimum distance between a point and a parametric surface, and then to return the nearest point (foot point) on the surface as well as its corresponding parameter, which is also called the point projection problem of a parametric surface. The geometric strategy algorithm (hereafter GSA) presented consists of two parts as follows. The normal curvature to a given parametric surface is used to find the corresponding foot point firstly, and then the Taylor's expansion of the parametric surface is employed to compute parameter increments and to get the iteration formula to calculate the orthogonal projection point of test point to the parametric surface. Our geometric strategy algorithm is essentially dependent on the geometric property of the normal curvature, and performs better than existing methods in two ways. Firstly, GSA converges faster than existing methods, such as the method to turn the problem into a root-finding of nonlinear system, subdividing methods, clipping methods, geometric methods (tangent vector and geometric curvature) and hybrid second-order method, etc. Specially, it converges faster than the classical Newton's iterative method. Secondly, GSA is independent of the initial iterative value, which we prove in Theorem 1. Many numerical examples confirm GSA's robustness and efficiency.展开更多
Molybdenum disulfide (MoS_(2)) has received enormous attentions in the electrochemical energy storage due to its unique two-dimensional layered structure and relatively high reversible capacity. However, the applicati...Molybdenum disulfide (MoS_(2)) has received enormous attentions in the electrochemical energy storage due to its unique two-dimensional layered structure and relatively high reversible capacity. However, the application of MoS_(2) in potassium-ion batteries (PIBs) is restricted by poor rate capability and cyclability, which are associated with the sluggish reaction kinetics and the huge volume expansion during K+ intercalation. Herein, we propose a two-dimensional (2D) space confined strategy to construct van der Waals heterostructure for superior PIB anode, in which the MoS_(2) nanosheets can be well dispersed on reduced graphene oxide nanosheets by leveraging the confinement effect within the graphene layers and amorphous carbon. The strong synergistic effects in 2D van der Waals heterostructure can extremely promote the electron transportation and ions diffusion during K+ insertion/extraction. More significantly, the 2D space-confinement effect and van der Waals force inhibit polysulfide conversion product dissolution into the electrolyte, which significantly strengthens the structural durability during the long-term cycling process. As anticipated, the as-synthesized the “face-to-face” C/MoS_(2)/G anode delivers remarkable K-storage performance, especially for high reversible capacity (362.5 mAh·g^(-1) at 0.1 A·g^(-1)), excellent rate capability (195.4 mAh·g^(-1) at 10 Ag^(-1)) and superior ultrahigh-rate long-cycling stability (126.4 mAh·g^(-1) after 4000 cycles at high rate of 5 A·g^(-1)). This work presents a promise strategy of structure designing and composition optimization for 2D layered materials in advanced energy storage application.展开更多
基金supported by the Natural Science Foundation of Jiangsu Province (BK20210887)the Jiangsu Provincial Double Innovation Program (JSSCB20210984)+1 种基金the Natural Science Fund for Colleges and Universities of Jiangsu Province (21KJB450003)the Jiangsu University of Science and Technology Doctoral Research Start-up Fund (120200012)。
文摘Higher nickel content endows Ni-rich cathode materials LiNi_(x)Co_yMn_(1-x-y)O_(2)(x>0.6)with higher specific capacity and high energy density,which is regarded as the most promising cathode materials for Li-ion batteries.However,the deterioration of structural stability hinders its practical application,especially under harsh working conditions such as high-temperature cycling.Given these circumstances,it becomes particularly critical to clarify the impact of the crystal morphology on the structure and high-temperature performance as for the ultrahigh-nickel cathodes.Herein,we conducted a comprehensive comparison in terms of microstructure,high-temperature long-cycle phase evolution,and high-temperature electrochemical stability,revealing the differences and the working mechanisms among polycrystalline(PC),single-crystalline(SC)and Al doped SC ultrahigh-nickel materials.The results show that the PC sample suffers a severe irreversible phase transition along with the appearance of microcracks,resulting a serious decay of both average voltage and the energy density.While the Al doped SC sample exhibits superior cycling stability with intact layered structure.In-situ XRD and intraparticle structural evolution characterization reveal that Al doping can significantly alleviate the irreversible phase transition,thus inhibiting microcracks generation and enabling enhanced structure.Specifically,it exhibits excellent cycling performance in pouch-type full-cell with a high capacity retention of 91.8%after 500 cycles at 55℃.This work promotes the fundamental understanding on the correlation between the crystalline morphology and high-temperature electrochemical stability and provides a guide for optimization the Ni-rich cathode materials.
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This work was supported by National Natural Science Foundation of China(51902347,51822812,51772334,51778627).
文摘Along with the extensive application of energy storage devices,the spent lithium-ion batteries(LIBs)are unquestionably classified into the secondary resources due to its high content of several valuable metals.However,current recycling methods have the main drawback to their tedious process,especially the purification and separation process.Herein,we propose a simplified process to recycle both cathode(LiCoO_(2))and anode(graphite)in the spent LIBs and regenerate newly high-performance anode material,CoO/CoFe2O4/expanded graphite(EG).This process not only has the advantages of succinct procedure and easy control of reaction conditions,but also effectively separates and recycles lithium from transition metals.The 98.43%of lithium is recovered from leachate when the solid product CoO/CoFe2O4/EG is synthesized as anode material for LIBs.And the product exhibits improved cyclic stability(890 mAh g^(-1) at 1 A g^(-1) after 700 cycles)and superior rate capability(208 mAh g^(-1) at 5 A g^(-1)).The merit of this delicate recycling design can be summarized as three aspects:the utilization of Fe impurity in waste LiCoO_(2),the transformation of waste graphite to EG,and the regeneration of anode material.This approach properly recycles the valuable components of spent LIBs,which introduces an insight into the future recycling.
基金financially supported by the National Natural Science Foundation of China(Nos.51822812,51778627)the Fundamental Research Funds for the Central Universities of Central South University(No.2020zzts474)。
文摘In this paper,the ammonia leaching process and high-energy ball milling method were adapted to recover spent LiCoO_(2) material.The ammonia reduction leaching mechanism of LiCoO_(2) material in the ammonia-sodium sulfite-ammonium chloride system was elucidated.Compared with untreated LiCoO_(2) material,the leaching equilibrium time of LiCoO_(2) after ball-milled for 5 h was reduced from 48 h to 4 h,and the leaching efficiency of lithium and cobalt was improved from 69.86%and 70.80%to 89.86%and98.22%,respectively.Importantly,the apparent activation energy and leaching kinetic equation of the reaction was calculated by the shrinking core reaction model,indicating that the reaction was controlled by the chemical reaction.
基金This work is supported by the National Natural Science Foundation of China under Grant No.61263034the Feature Key Laboratory for Regular Institutions of Higher Education of Guizhou Province of China under Grant No.[2016]003+3 种基金the Key Laboratory of Advanced Manufacturing Technology of Ministry of Education of China with Guizhou University under Grant No.KY[2018]479the Training Center for Network Security and Big Data Application of Guizhou Minzu University under Grant No.20161113006the Shandong Provincial Natural Science Foundation of China under Grant No.ZR2016GM24the Progress Project for Young Science and Technology Scholars of Guizhou Provincial Department of Education under Grant No.KY[2016]164.
文摘In this paper, we investigate how to compute the minimum distance between a point and a parametric surface, and then to return the nearest point (foot point) on the surface as well as its corresponding parameter, which is also called the point projection problem of a parametric surface. The geometric strategy algorithm (hereafter GSA) presented consists of two parts as follows. The normal curvature to a given parametric surface is used to find the corresponding foot point firstly, and then the Taylor's expansion of the parametric surface is employed to compute parameter increments and to get the iteration formula to calculate the orthogonal projection point of test point to the parametric surface. Our geometric strategy algorithm is essentially dependent on the geometric property of the normal curvature, and performs better than existing methods in two ways. Firstly, GSA converges faster than existing methods, such as the method to turn the problem into a root-finding of nonlinear system, subdividing methods, clipping methods, geometric methods (tangent vector and geometric curvature) and hybrid second-order method, etc. Specially, it converges faster than the classical Newton's iterative method. Secondly, GSA is independent of the initial iterative value, which we prove in Theorem 1. Many numerical examples confirm GSA's robustness and efficiency.
基金This work was financially supported by the National Natural Science Foundation of China(Nos.51902347,51822812,51772334,and 51778627)Natural Science Foundation of Hunan Province(No.2020JJ5741).
文摘Molybdenum disulfide (MoS_(2)) has received enormous attentions in the electrochemical energy storage due to its unique two-dimensional layered structure and relatively high reversible capacity. However, the application of MoS_(2) in potassium-ion batteries (PIBs) is restricted by poor rate capability and cyclability, which are associated with the sluggish reaction kinetics and the huge volume expansion during K+ intercalation. Herein, we propose a two-dimensional (2D) space confined strategy to construct van der Waals heterostructure for superior PIB anode, in which the MoS_(2) nanosheets can be well dispersed on reduced graphene oxide nanosheets by leveraging the confinement effect within the graphene layers and amorphous carbon. The strong synergistic effects in 2D van der Waals heterostructure can extremely promote the electron transportation and ions diffusion during K+ insertion/extraction. More significantly, the 2D space-confinement effect and van der Waals force inhibit polysulfide conversion product dissolution into the electrolyte, which significantly strengthens the structural durability during the long-term cycling process. As anticipated, the as-synthesized the “face-to-face” C/MoS_(2)/G anode delivers remarkable K-storage performance, especially for high reversible capacity (362.5 mAh·g^(-1) at 0.1 A·g^(-1)), excellent rate capability (195.4 mAh·g^(-1) at 10 Ag^(-1)) and superior ultrahigh-rate long-cycling stability (126.4 mAh·g^(-1) after 4000 cycles at high rate of 5 A·g^(-1)). This work presents a promise strategy of structure designing and composition optimization for 2D layered materials in advanced energy storage application.
