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Aiming at the consumption problems caused by the high proportion of renewable energy being connected to the distribution network, it also aims to improve the power supply reliability of the power system and reduce the operating costs of the power system. This paper proposes a two-stage planning method for distributed generation and energy storage systems that considers the hierarchical partitioning of source-storage-load. Firstly, an electrical distance structural index that comprehensively considers active power output and reactive power output is proposed to divide the distributed generation voltage regulation domain and determine the access location and number of distributed power sources. Secondly, a two-stage planning is carried out based on the zoning results. In the phase 1 distribution network-zoning optimization layer, the network loss is minimized so that the node voltage in the area does not exceed the limit, and the distributed generation configuration results are initially determined; in phase 2, the partition-node optimization layer is planned with the goal of economic optimization, and the distance-based improved ant lion algorithm is used to solve the problem to obtain the optimal distributed generation and energy storage system configuration. Finally, the IEEE33 node system was used for simulation. The results showed that the voltage quality was significantly improved after optimization, and the overall revenue increased by about 20.6%, verifying the effectiveness of the two-stage planning. [ABSTRACT FROM AUTHOR]

Co-MoP/PCNFs modified Celgard separator in Lithium-sulfur battery. [Display omitted] Rational design of separators is especially critical to solve the "shuttle effect" of lithium polysulfides (LiPSs) and the sluggish redox kinetics in lithium-sulfur batteries (LSBs). Here, the multi-functional nanocomposite involving Co-doped molybdenum phosphide (Co-MoP) nanofibers and porous carbon nanofibers (PCNFs) is designed and prepared through electro-blow spinning and phosphating process, which possesses multiple adsorption and catalytic sites and is acted as the functional material for LSBs separators. In this multifunctional nanocomposite, the prepared Co-MoP nanofibers can provide internal adsorption and catalytic sites for LiPSs conversion. And the interconnected nitrogen-doped PCNFs can be elaborated an efficient LiPSs mediator and accommodate the huge volume changes in the reaction process for LSBs. Benefiting from the multiple adsorptive and catalytic sites of the developed functional materials, the assembled LSBs with a Co-MoP/PCNFs modified separator display outstanding electrochemical performances, including an admirable capacity retention of 770.4 mAh g−1 after 400 cycles at 1.0 C, only 0.08 % capacity decay per cycle at 2.0 C, rate performance up to 5 C, and also decent areal capacity even under a high sulfur loading of 4.9 mg cm−2. The work provides a facile pathway towards multifunctional separators in LSBs, and it may also help deepen preparation method of MoP through the electrostatic blowing/electrospinning technology in other related energy storage fields. [ABSTRACT FROM AUTHOR]

YF 3 /CoF 3 co-doped 1D carbon nanofibers as S host. [Display omitted] Lithium-sulfur (Li-S) batteries have attracted extensive attention in the field of energy storage due to their high energy density and low cost. However, conundrums such as severe polarization, poor cyclic performance originating from shuttle effect of lithium polysulfides and sluggish sulfur redox kinetics are stumbling blocks for their practical application. Herein, a novel sulfur cathode integrating sulfur and polyvinylpyrrolidone(PVP)-derived N -doped porous carbon nanofibers (PCNFs) with embedded CoF 3 and YF 3 nanoparticles are designed and prepared though the electrostatic blowing technology and carbonization process. The unique flexible PCNFs with embedded polar CoF 3 and YF 3 nanoparticles not only offer enough voids for volume expansion to maintain the structural stability during the electrochemical process, but also promote the physical encapsulation and chemical entrapment of all sulfur species. Moreover, the uniform distribution of YF 3 /CoF 3 nanoparticles also can expose more binding active sites to lithium polysulfide and present more catalytic sites to the greatest extent. Therefore, the assembled cells with the prepared cathode exhibited stable performances with an outstanding initial capacity of 1055.2 mAh g−1 and an extended cycling stability of 0.029% per cycle during the 300 cycles at 0.5C. Even at a high sulfur loading of 2.1 mg cm−2, The YF 3 /CoF 3 doped-PCNFs exhibited a high discharge specific capacity of 1038 mAh g−1, and the decay rate is also as low as 0.05% over 1000 cycles. This work shares a convenient and safe strategy for the synthesis of multi-dimension, dual-functional and stable superstructure electrode for advanced Li-S batteries. [ABSTRACT FROM AUTHOR]

Lithium‐sulfur (Li−S) batteries, possessing excellent theoretical capacities, low cost and nontoxicity, are one of the most promising energy storage battery systems. However, poor conductivity of elemental S and the "shuttle effect" of lithium polysulfides hinder the commercialization of Li−S batteries. These problems are closely related to the interface problems between the cathodes, separators/electrolytes and anodes. The review focuses on interface issues for advanced separators/electrolytes based on nanomaterials in Li−S batteries. In the liquid electrolyte systems, electrolytes/separators and electrodes system can be decorated by nano materials coating for separators and electrospinning nanofiber separators. And, interface of anodes and electrolytes/separators can be modified by nano surface coating, nano composite metal lithium and lithium nano alloy, while the interface between cathodes and electrolytes/separators is designed by nano metal sulfide, nanocarbon‐based and other nano materials. In all solid‐state electrolyte systems, the focus is to increase the ionic conductivity of the solid electrolytes and reduce the resistance in the cathode/polymer electrolyte and Li/electrolyte interfaces through using nanomaterials. The basic mechanism of these interface problems and the corresponding electrochemical performance are discussed. Based on the most critical factors of the interfaces, we provide some insights on nanomaterials in high‐performance liquid or state Li−S batteries in the future. [ABSTRACT FROM AUTHOR]

[Display omitted] • S2− doped Co(OH) 2 is prepared by transforming Co 3 O 4 to Co(OH) 2 in Na 2 S solution. • The suppressed bulk phase transformation renders the feature of surface reaction. • The surface-absorbed H 2 O leads to the feature of decreased interaction with OH− ions. • The above two features result in the pseudocapacitive properties of S2− doped Co(OH) 2. Some battery-type materials show the potential for storing high density energy in supercapacitors because of their high theoretical capacity. So far, the very unsatisfied electrochemical performance is still the label of these battery-type materials, which is attributed to their diffusion-controlled kinetics of energy storage. Some efforts try to transform their electrochemical behavior to extrinsic pseudocapacitive behavior through nanostructuring. However, the extrinsic pseudocapacitive materials are rare due to the restriction of no phase transformation. In this work, we propose an alternative strategy to create an extrinsic pseudocapacitive material from the typical battery-type material Co(OH) 2 by S2− doping. The doped S2− ions further increase energy barrier for the intercalation of OH− ions into the interlayer space of Co(OH) 2 , thus suppressing its bulk phase transformation. Also, the decreased OH− ions-Co(OH) 2 interaction plus the surface reaction feature induced by S2− doping results in the pseudocapacitive behavior. Thus, the S2− doped Co(OH) 2 presents the comprehensive electrochemical signatures of pseudocapacitive materials and an extraordinary cycling life of 200,000 charge-discharge cycles. This work initiates a new way for acquiring electrode materials with high electrochemical performance for application in supercapacitors. [ABSTRACT FROM AUTHOR]

MoP-MoO 2 /PCNFs modified Celgard separator in Lithium-sulfur battery. [Display omitted] • Investigating on the formation process of the heterostructured MoP-MoO 2 nanobelts. • Exploring the functions of various Mo-based heterojunctions in Li-S batteries. • Synergistic effect of LiPS desorption based PCNFs and heterostructured MoP-MoO 2. • The LSB with MoP-MoO 2 /PCNFs presents 856.9 mAh g−1 at 1C after 400 cycles. Lithium-sulfur batteries have ultra-high theoretical energy densities, which make them one of the most promising next-generation energy storage systems. However, it is still difficult to achieve large-scale commercialization because of fast capacity fade and poor rate capabilities. These problems are mainly caused by the severe shuttle effect of lithium polysulfide (LiPS) and slow redox kinetics. To solve these barriers, herein a modification strategy of functional separator is prepared by coating heterostructured and defective MoP-MoO 2 with porous carbon nanofibers (PCNFs) on the surface of a commercial separator. Moreover, for the first time, we detailly explored the formation processes of various heterojunction (MoP-MoO 2 , Mo 3 P-MoO 2 and MoP-Mo 3 P) derived from MoO 3 nanobelts and put forward some conceptions for the constituting heterostructured MoP-MoO 2 through the phosphorization of MoO 3 precursor. The functional coating layer exhibits both satisfactory interception ability for LiPS shuttle and fast LiPS conversion ability due to abundant anchoring sites of heterostructured MoP-MoO 2 nanobelts and shortened lithium ion channels of the prepared PCNFs. Benefiting from these advantages, the assembled Li-S battery with MoP-MoO 2 /PCNFs separator delivered a high specific capacity of 1078.9 mAh g−1 at 1C and 1056.7 mAh g−1 at 2C, excellent cycling stability (856.9 mAh g−1 after 400 cycles at 1C and 630.1 mAh g−1 after 500 cycles at 2C). The cell with MoP-MoO 2 /PCNFs separator manifested outstanding cycle performance with fading rate of 0.08 % at 0.5C after 300 cycles under a sulfur loading of 4.0 mg cm−2. The novel work will provide a new strategy by which the modified separator with the heterostructured transition metal phosphides and oxides can be applied for high-performance Li–S batteries and shows great potential for practical application. [ABSTRACT FROM AUTHOR]

Lithium-sulfur batteries (LSBs) have attracted increasing attention due to high theoretical energy density and low cost of sulfur. However, there are still many challenges regarding sulfur cathodes such as the "shuttle effect" of polysulfides, insulating properties of sulfur and Li 2 S 2 /Li 2 S, and the sluggish redox kinetics. In this study, the nanorod-like Sb-doped SnO 2 nanofibers (ATO NFs) with hollow structure were prepared by the electro-blown spinning technology and calcination processes, and used as a sulfur host for cathode materials. The internal hollow structure and the nanorod-like structure on the surface of the nanofibers with the increased specific surface area are beneficial to load sulfur and improve transport channels of electrons and lithium ions. And the hollow nanofibers also can well accommodate to huge volume changes in the reaction process. More importantly, the ATO NFs with hollow structure have good physical confinement and chemical adsorption performance to polysulfides. Based on these merits, the ATO NFs composite cathode exhibits a high initial discharge specific capacity of 765.3 mAh g−1 and maintains 550.6 mAh g−1 after 900 cycles at a rate of 2 C with 1.9 mg cm−2 sulfur loading. More importantly, high initial area discharge specific capacity of the electrode is 5.5 mAh cm−2 at 0.1 C with sulfur loading of 5.6 mg cm−2. Even, at a rate of 0.2 C, the area capacity still is stabilized at 3.5 mAh cm−2 after 100 cycles. The work illustrates that the ATO NFs for LSBs exhibit good cycling stability over a long period of time, entering the ranks of high performance and ultra-stable capacity. And it also facilitate to expand the scope of application of ATO NFs in other related energy storage fields. [Display omitted] • A novel nanorod-like Sb-doped SnO 2 nanofibers is successfully designed and prepared. • The prepared ATO are beneficial to load sulfur and enhance transport channels of electrons and lithium ions. • The ATO based electrode can greatly suppress shuttle effect of polysulfides and play important in catalytic conversion. • The assembled Li-S battery with the ATO based electrode presents stable long-term cycle performance. [ABSTRACT FROM AUTHOR]

• The different fabrication techniques of nanofiber materials are summarized. • The functional action mechanisms of nanofibers for inhibiting Li dendrites are reviewed. • Various protection strategies of nanofiber materials to suppress the Li dendrites growth are summarized. • The challenges and prospects of nanofiber materials for Li anode are discussed. Lithium metal batteries (LMBs) are regarded as one of the most promising candidates for next-generation energy storage systems. However, the uncontrolled dendritic lithium (Li) growth lead to low Coulombic efficiency and security issue, thus limiting the commercial applications of LMBs. Owing to the unique nanostructure characteristics, nanofiber materials offer innovative strategies and opportunities to resolve the tricky challenge. A comprehensive review of the fundamental researches and technological developments of various nanofiber materials for LMBs was presented in this paper. The fabrication techniques of nanofibers and several functional action mechanisms for inhibiting dendritic Li were outlined. Then the different protection technologies of nanofiber materials for LMBs to suppress the Li dendrites growth were summarized, which included modifying separators, introducing functional interlayers and constructing novel composite anodes and current collectors. Meanwhile, the electrochemical performances using different strategies of the overall LMBs were discussed. Finally, the current challenges and prospects of nanofiber materials for Li anode were discussed. These discussions and proposed strategies will enlighten thoughts and offer ways to the practical application of LMBs with excellent electrochemical performances in the future. [ABSTRACT FROM AUTHOR]