The demands for better energy storage devices due to fast development of electric vehicles(EVs) have raised increasing attention on lithium ion batteries(LIBs) with high power and energy densities. In this paper, we p...The demands for better energy storage devices due to fast development of electric vehicles(EVs) have raised increasing attention on lithium ion batteries(LIBs) with high power and energy densities. In this paper, we provide an overview of recent progress in graphene-based electrode materials. Graphene with its great electrical conductivity and mechanical properties have apparently improved the performance of traditional electrode materials. The methods and electrochemical properties of advanced graphene composite as cathode and anode for LIBs are reviewed. Two novel kinds of graphene hybrid materials are specially highlighted: three-dimensional porous and flexible binder-free graphene-based materials. Challenges for LIBs and future research trend in the development of high-performance electrode materials are further discussed.展开更多
The aim of this study is to formulate an appropriate free energy potential for inelastic behavior of concrete and construct an elastoplastic damage model on a more rational basis. The concept of effective plastic ener...The aim of this study is to formulate an appropriate free energy potential for inelastic behavior of concrete and construct an elastoplastic damage model on a more rational basis. The concept of effective plastic energy storage rates is proposed, which are conjugate forces of hardening variables in an undamaged configuration. Then an analogy between the evolution of harden- ing variables and that of a plastic strain is used to postulate the formulation of plastic free energy. This formulation reflects the specific characteristics of a certain plasticity model, so it can serve well as a thermodynamic link between plasticity and dam- age. By combination of the general formulation of free energy with the double hardening plasticity theory and two-parameter damage expression, a thermodynamically well-founded elastoplastic damage model for concrete is constructed. The operator split algorithm is emploved, and the numerical simulations a^ree well with a series of material tests.展开更多
Lithium-sulfur batteries have been widely nominated as one of the most promising next-generation electrochemical storage systems due to its low cost, high capacity and energy density. However, its practical applicatio...Lithium-sulfur batteries have been widely nominated as one of the most promising next-generation electrochemical storage systems due to its low cost, high capacity and energy density. However, its practical application is still hindered by poor cycling lifetime, low Coulombic efficiency, instability and small scales. In the last decade, the electrochemical performances of the lithium-sulfur batteries have been improved by developing various novel nanoarchitectures as qualified hosts, and enhancing the sulfur loading with effective encapsulating strategies. The review summarizes the major sulfur cooperating strategies of cathodes based on background and latest progress of the lithium-sulfur batteries. The novel cooperating strategies of physical techniques and chemical synthesis techniques are discussed in detail. Based on the rich chemistry of sulfur, we paid more attention to the highlights of sulfur encapsulating strategies. Furthermore, the critical research directions in the coming future are proposed in the conclusion and outlook section.展开更多
基金supported by the National Hi-Tech Research and Development Program of China("863"Project)(Grant No.2012CB932303)Shanghai Municipal Natural Science Foundation(Grant Nos.13ZR1463600&13XD1403900)
文摘The demands for better energy storage devices due to fast development of electric vehicles(EVs) have raised increasing attention on lithium ion batteries(LIBs) with high power and energy densities. In this paper, we provide an overview of recent progress in graphene-based electrode materials. Graphene with its great electrical conductivity and mechanical properties have apparently improved the performance of traditional electrode materials. The methods and electrochemical properties of advanced graphene composite as cathode and anode for LIBs are reviewed. Two novel kinds of graphene hybrid materials are specially highlighted: three-dimensional porous and flexible binder-free graphene-based materials. Challenges for LIBs and future research trend in the development of high-performance electrode materials are further discussed.
基金supported by the National Natural Science Foundation of China(Grant Nos.51261120374,51108336 and 51378377)
文摘The aim of this study is to formulate an appropriate free energy potential for inelastic behavior of concrete and construct an elastoplastic damage model on a more rational basis. The concept of effective plastic energy storage rates is proposed, which are conjugate forces of hardening variables in an undamaged configuration. Then an analogy between the evolution of harden- ing variables and that of a plastic strain is used to postulate the formulation of plastic free energy. This formulation reflects the specific characteristics of a certain plasticity model, so it can serve well as a thermodynamic link between plasticity and dam- age. By combination of the general formulation of free energy with the double hardening plasticity theory and two-parameter damage expression, a thermodynamically well-founded elastoplastic damage model for concrete is constructed. The operator split algorithm is emploved, and the numerical simulations a^ree well with a series of material tests.
基金supported by the National Natural Science Foundation of China(Grant No.21303038)Open Funds of the State Key Laboratory of Rare Earth Resource Utilization(Grant No.RERU2016004)+1 种基金Scientific Research Foundation for the Returned Overseas Chinese Scholars,State Education Ministry(Grant No.JZ2015JYLH0082)Qingdao Think-Tank Union Funds for Energy Storage(Grant No.JZ2016QTXM1097)
文摘Lithium-sulfur batteries have been widely nominated as one of the most promising next-generation electrochemical storage systems due to its low cost, high capacity and energy density. However, its practical application is still hindered by poor cycling lifetime, low Coulombic efficiency, instability and small scales. In the last decade, the electrochemical performances of the lithium-sulfur batteries have been improved by developing various novel nanoarchitectures as qualified hosts, and enhancing the sulfur loading with effective encapsulating strategies. The review summarizes the major sulfur cooperating strategies of cathodes based on background and latest progress of the lithium-sulfur batteries. The novel cooperating strategies of physical techniques and chemical synthesis techniques are discussed in detail. Based on the rich chemistry of sulfur, we paid more attention to the highlights of sulfur encapsulating strategies. Furthermore, the critical research directions in the coming future are proposed in the conclusion and outlook section.
