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Organic compounds have become a potentially important choice for a new generation of energy-storage electrode materials due to their designability, flexibility, green sustainability, and abundance. However, the applications of organic electrode materials are still limited because of their dissolution in electrolytes and low electrical conductivity, which in turn cause poor cycling stability. Here, for the first time, we report 2-amino-4-thiazole-acetic acid (ATA) and its sodium salt, sodium 2-amino-4-thiazol-derived polymer (PATANa), as an anode. The PATANa showed a two-dimensional (2D) nanosheet structure, offering a larger contact area with the electrolyte and a shorter ion-migration path, which improved the ion-diffusion kinetics. The polymer showed excellent cycling stability and outstanding rate capability when tested as an anode for sodium-ion batteries (SIBs). It could deliver a high reversible specific capacity of 303 mA h g−1 at 100 mA g−1 for 100 cycles and maintain a high discharge capacity of 190 mA h g−1 after 1000 long cycle numbers even at a high current density of 1000 mA g−1. This approach of salinizing the polymer opens a new way to develop anode materials for sodium-ion batteries. [ABSTRACT FROM AUTHOR]

Transition-metal sulfides have been considered as promising candidates for electrochemical supercapacitor and lithium ion batteries. Unfortunately, the shortcomings including large volume change, low conductivity as well as severe structural exfoliation from conductive substrate or current collector inhibit their practical application. Herein, the hydrothermal and solvothermal approach are developed for the controllable synthesis of core-shell NiCo 2 S 4 @C with three dimensional carbon frameworks. As an asymmetric supercapacitor, the NiCo 2 S 4 @C/YP-50 F displays a high energy density of 46.7 Wh kg−1 at a power density of 0.8 kW kg−1 and the good cycling stability (∼110 % of the initial capacitance retention at 16 kW kg−1 over 2000 cycles). Furthermore, the NiCo 2 S 4 @C exhibits the specific capacity of 414 mAh g−1 after 500 cycles at 2000 mA g−1 when evaluated as anode for lithium ion batteries. The excellent performance can be ascribed to the core-shell structure and the three dimensional carbon frameworks. The synthetic approach can be extended to fabricate other high performance metal sulfides for energy storage. [Display omitted] • Core-shell NiCo 2 S 4 @C with three dimensional carbon framework is synthesized. • The 3D carbon framework maintains the structure integrity and improves the electrical conductivity. • The chemical bonds of Co-C/Ni-C inhibits the structural exfoliation from carbon. • The core-shell NiCo 2 S 4 @C exhibits excellent electrochemical performance. [ABSTRACT FROM AUTHOR]

Developing highly efficient host materials to suppress the lithium polysulfides (LiPSs) shuttling and accelerate the Li 2 S conversion is essential for advanced lithium-sulfur (Li–S) batteries. In this work, based on first principles computations, we explored transition metal embedded C 2 N monolayers (M@C 2 N, M = Mn, Fe, Co, Ni, Cu) as host materials and catalysts for Li–S batteries. Our results show that M@C 2 N monolayers could prevent the LiPSs shuttling with strong adsorption energies towards LiPSs, due to the synergistic effect of M-S and Li–N bonds. Moreover, the presence of transition metal atoms in the C 2 N could improve its electric conductivity. On the whole lithiation process, all the adsorbed systems are still conductive, which is helpful to boost the sulfur utilization. Importantly, M@C 2 N monolayers could promote the Li 2 S decomposition and thus enhance the oxidation kinetics of Li 2 S back to sulfur. Among them, Co@C 2 N monolayer is the best host material, which possesses the largest adsorption energies with LiPSs and the lowest decomposition energy of Li 2 S. This work opens a new avenue for the development of host materials with excellent catalytic activity towards LiPSs, and also sheds light on M@C 2 N as superior cathode materials. [ABSTRACT FROM AUTHOR]

Copper selenide as an anode for lithium-ion batteries suffers from volume expansion/contraction, while constructing nanostructured copper selenide with other components is considered as an effective strategy. In this work, Cu2−xSe@C@Sb2Se3 nanosheets were fabricated through a two step solvothermal procedure with the assistance of glucose. Such a structure can facilitate the migration rate of Li+, enhance the electrical conductivity, buffer the volume variation and prohibit the aggregation of the electrode. As a result, Cu2−xSe@C@Sb2Se3 exhibits good electrochemical performance with a specific capacity of 341 mA h g−1 after 100 cycles at a current density of 100 mA g−1 and 153 mA h g−1 at a rate of 2000 mA g−1. Such a structural design and synthetic strategy may also be applied to explore other nanocomposites to improve the electrochemical performance. [ABSTRACT FROM AUTHOR]

The design and fabrication of the materials to improve their performance are crucial for energy storage of lithium-ion batteries and supercapacitors. Herein, the CuCo 2 S 4 nanocrystallites grown on N-doped amorphous carbon coated CNTs are synthesized via a facile solvothermal method (CNTs@NC@CuCo 2 S 4 ). The N-doped amorphous carbon layer with functional groups can effectively strengthen the adhesion between CNTs matrix and CuCo 2 S 4 nanocrystallites. The combination of nanocrystallites and the CNTs not only shortens the diffusion path of the electrolyte, but also enhances the electrical conductivity of the electrode. As a result, the CNTs@NC@CuCo 2 S 4 displays excellent electrochemical performance both in lithium-ion batteries and supercapacitors. The reversible capacity can be retained at 783 mAh g −1 after 100 cycles at the current density of 100 mA g −1 . And the discharge capacity of 507 mAh g −1 is still maintained after 60 cycles even at high rate of 5000 mA g −1 . As the electrode for supercapacitors, the CNTs@NC@CuCo 2 S 4 delivers good capacitive performance with high capability (1604 F g -1  at 1 A g −1 ), good rate capability, and enhanced cycling stability, with 93.6% capacitance retention after 2000 cycles at the current density of 2 A g −1 . [ABSTRACT FROM AUTHOR]

One dimensional CNTs@C@MFe 2 O 4 (M = Ni, Co) composites have been rationally designed and fabricated via a facile solvothermal method and a calcination process. In the unique structure, amorphous carbon served as binder can increase the loading of MFe 2 O 4 on CNTs and strengthened the binding of MFe 2 O 4 and CNTs. As anode materials for lithium ion batteries, the CNTs@C@MFe 2 O 4 delivers a high specific capacity, excellent cycling stability and high rate capacity. The enhanced electrochemical performance can be attributed to the uniform dispersion of MFe 2 O 4 nanoparticles on the amorphous carbon coated CNTs, which can improve contact area between the MFe 2 O 4 nanoparticles and the electrolyte, enhance electrical conductivity, buffer the volume change maintain the structural integrity of the electrodes. Meanwhile, the lithiation and delithiation processes are systematically investigated by X-ray photoelectron spectroscopy analysis and transmission electron microscope technique. Furthermore, the efficient synthesis process developed here can also be extended to design and synthesize other transition metal oxides/carbon nanotube functional materials. [ABSTRACT FROM AUTHOR]

Cobalt sulfide and molybdenum sulfide, with high theoretical capacities, have been considered as one of most promising anode materials for lithium-ion batteries (LIBs). However, the poor cyclability and low rate performances originating from the large volume expansion and poor electrical conductivity extremely inhibit their practical application. Here, the electrochemical performances are effectively improved by growing amorphous cobalt sulfide and molybdenum sulfide onto amorphous carbon-coated multiwalled carbon nanotubes (CNTs@C@CoS2 and CNTs@C@MoS2). The CNTs@C@CoS2 presents a high reversible specific capacity of 1252 mAh g−1 at 0.2 Ag−1, excellent rate performance of 672 mAh g−1 (5 Ag−1), and enhanced cycle life of 598 mAh g−1 after 500 cycles at 2 Ag−1. For CNTs@C@MoS2, it exhibits a specific capacity of 1395 mAh g−1, superior rate performance of 727 mAh g−1 at 5 Ag−1, and long cycle stability (796 mAh g−1 after 500 cycles at 2 Ag−1). The enhanced electrochemical properties of the electrodes are probably ascribed to their amorphous nature, the combination of CNTs@C that adhered and hindered the agglomeration of CoS2 and MoS2 as well as the enhanced electronic conductivity. [ABSTRACT FROM AUTHOR]

• The C 3 N/BlueP heterostructure as an anode material for Li-ion batteries combines the advantages of C 3 N and BlueP. • Enhanced electrical conductivity and mechanical stability are observed in the C 3 N/BlueP heterostructure. • The C 3 N/BlueP heterostructure possesses a high specific capacity of 1092 mA h/g and low diffusion barrier of 0.12 eV. Two dimensional heterostructures could not only combine each other's advantages, but also compensate for their drawbacks. In this work, we systematically investigated the C 3 N/blue phosphorene (C 3 N/BlueP) heterostructure as an anode material for Li-ion batteries (LIBs) based on the comprehensive first principles computations. Our results show that the C 3 N/BlueP heterostructure possesses good structural stability and ultra-high stiffness (Y x = 417.3 N/m). The band gap of C 3 N/BlueP heterostructure is 0.026 eV, exhibiting good electrical conductivity for fast electron transport. Attributed to the synergistic effect, the adsorption energy of Li in the interface region of C 3 N/BlueP heterostructure (−2.057 to −1.898 eV) is greatly increased in comparison with pristine C 3 N (−0.563 eV) and BlueP (−1.852 eV). Consequently, the specific capacity is up to 1092 mA h/g, which far exceeds those of other BlueP-based heterostructures and commercial graphite (372 mA h/g). Additionally, the diffusion barrier for the C 3 N/BlueP heterostructure is only 0.12 eV, implying fast Li migration. Given these exceptional properties, that is, good electrical conductivity, ultra-high stiffness, high specific capacity and low diffusion barrier, it could be concluded that the C 3 N/BlueP heterostructure is an appealing anode material for high-performance LIBs. [ABSTRACT FROM AUTHOR]

NC@NiMoS 4 nanocomposites have been firstly designed and fabricated by anchoring NiMoS 4 nanoparticles on N doped carbon nanosheets, which delivers high and stable reversible capacity and excellent rate performance. Owing to the excellent electrical conductivity and high theoretical capacity, binary transition metal sulfides have attracted extensive attention as promising anodes for lithium ion batteries (LIBs). However, the relatively poor electrical conductivity and serious capacity fading originated from large volume change still hinder their practical applications. Herein, binary NiMoS 4 nanoparticles are deposited on N doped carbon nanosheets (NC@NiMoS 4) through a facile hydrothermal method. The N doped carbon nanosheets and the strong chemical bonding between NC and NiMoS 4 can accommodate the volume change, keep the structural integrity and promote the ion/electron transfer during electrochemical reaction. The extra voids between NiMoS 4 nanoparticles enlarge the contact area and reduce the lithium migration barriers. As anode for LIBs, the NC@NiMoS 4 exhibits the excellent cycle stability with 834 mAh g−1 after 100 cycles at the current density of 100 mA g−1. Even at high rate of 2000 mA g−1, the specific capacity of 544 mAh g−1 can be achieved after 500 cycles. [ABSTRACT FROM AUTHOR]

Due to the high specific capacity and low open circuit voltage (OCV), 2D siligraphene has been widely considered as a promising anode material for metal ion batteries (MIBs). Nonetheless, its electrochemical performance is greatly impeded by low mechanical stiffness, poor hopping dynamics and small pore size. Motivated by the great success of 3D carbon materials, we propose a metallic porous 3D-SiC anode using the corresponding 2D tetragonal SiC as a structural unit. By first principles molecular dynamics, mechanical property and phonon spectrum calculations, it is found that 3D-SiC possesses good thermal, mechanical and dynamical stability. The maximum Young's and bulk moduli of 3D-SiC are 217.16, 400.90 GPa, respectively, exhibiting a moderate mechanical stiffness. More importantly, the intrinsically high electrical conductivity, unique porous structure and low mass density make the 3D-SiC a promising anode candidate for Li/Na/K-ion batteries with small volume changes (6.43 %, 3.75 % and 8.66 %), low diffusion barriers (0.17, 0.19 and 0.017 eV), high storage capacities (947, 947 and 724 mA h/g) and low average OCVs (0.56, 0.34 and 0.11 V). The encouraging results show that siligraphene-based porous 3D anodes are worthy of further investigation for MIBs. [Display omitted] • The porous 3D-SiC is an appealing anode material for Li/Na/K-ion batteries. • Low diffusion barriers of 0.17, 0.19 and 0.017 eV. • Low average open-circuit-voltages of 0.56, 0.34 and 0.11 V. • High storage capacities of 947, 947 and 724 mA h/g. [ABSTRACT FROM AUTHOR]

[Display omitted] • The electrochemical performance of monolayer (bilayer) SiC 3 and SiC 5 as anodes of potassium ion batteries is systematically investigated. • Siligraphene possesses excellent mechanical property, good electrical conductivity, high ionic mobility and suitable open circuit voltage. • The specific capacities of monolayer (bilayer) SiC 3 and SiC 5 are 1151.61 (628.15), 1065.95 (609.11) mA h/g, respectively. • Siligraphene is a promising anode to achieve high-performance potassium ion batteries. Potassium ion batteries (PIBs) show great promise in the next-generation renewable energy storage owing to the high energy density, earth abundance and low cost of potassium; however, the lack of an appropriate anode material is a major obstacle to realize high-performance PIBs. Herein, on the base of first-principles computations, we systematically explored the feasibility of emerging 2D SiC 3 and SiC 5 (called siligraphene) as the anodes of PIBs. Our computational results reveal that potassium atoms could be stably adsorbed on monolayer (bilayer) SiC 3 and SiC 5 with the adsorption energy in the range of −0.32 - −0.04 eV. Benefiting from the semi-metallic nature, the SiC 3 (SiC 5) monolayer could provide excellent conductivity for rapid electron transport. Moreover, the potassium diffusion barrier on SiC 3 (SiC 5) is only 0.12 (0.028) eV, indicative of a fast charging/discharging capability. The theoretical capacities of monolayer (bilayer) SiC 3 and SiC 5 are up to 1151.61 (628.15), 1065.95 (609.11) mA h/g. Meanwhile, the good mechanical property and favorable structural recovery of SiC 3 (SiC 5)-based 2D materials indicate an excellent cycle reversibility. All the encouraging results suggest that SiC 3 (SiC 5) could be utilized as an outstanding anode for advanced PIBs. [ABSTRACT FROM AUTHOR]

• B 2 P 2 possesses semimetal nature, moderate Young's modulus and excellent mechanical flexibility. • B 2 P 2 exhibits low ion diffusion barriers and open circuit voltage. • The theoretical capacities of B 2 P 2 in Na, K and Ca-ion batteries are 1282.34, 854.89, 1282.34 mA h/g, respectively. • B 2 P 2 is a promising Dirac anode to achieve high-performance Na, K and Ca-ion batteries. Non-lithium ion batteries (NLIBs) have received great interest in the next generation renewable energy storage due to their intrinsic safety and low cost; nonetheless, searching for a high-performance anode still remains a great challenge. Herein, using first principles calculations, we have evaluated the feasibility of recently developed borophosphene (B 2 P 2) as a Dirac anode of NLIBs. Our results demonstrate that Na, K, Ca could form stable adsorption on the B 2 P 2 along with the adsorption energy of −1.27 – −0.36 eV. The B 2 P 2 exhibits a semimetal characteristic, ensuing excellent conductivity for the rapid electron transport. Moreover, diffusion barriers of Na, K and Ca are 0.10, 0.07 and 0.33 eV, respectively, indicative of high ion mobility. The specific capacities in Na, K and Ca-ion batteries are up to 1282.34, 854.89 and 1282.34 mA h/g, which are significantly larger than that of commercial electrode. Furthermore, B 2 P 2 could withstand large ultimate strain (>16%) and shows a good mechanical flexibility, which are of great benefit to accommodate its volumetric expansion and contraction during cycling. Given its high electrical conductivity, large adsorption energy, high specific capacity, fast ion diffusion and excellent mechanical property, B 2 P 2 is a potential anode to achieve advanced Na, K and Ca-ion batteries. [ABSTRACT FROM AUTHOR]

Janus MoSSe monolayer has been widely considered as an appealing anode for lithium-ion batteries (LIBs), owing to its suitable open circuit voltage, low diffusion barrier and high specific capacity. However, Janus MoSSe suffers from low electrical conductivity and poor mechanical property, resulting in a rapid capacity decay during cycling. Thus, in this work, we proposed two MoSSe/graphene (SMoSe/G and SeMoS/G) heterostructures as anodes of LIBs, which not only eliminate the drawbacks of MoSSe but also integrate the advantages of individual components. By means of first principles computations, we have systematically investigated the structural, electronic, mechanical and electrochemical properties of MoSSe/graphene heterostructures. Our results show that MoSSe/graphene heterostructures possess good structural stability, superior Li-ion conductivity and high mechanical stiffness (Y x (y) , S M o S e / G =459.8 N/m; Y x (y) , S e M o S / G = 459.3 N/m). Due to the synergistic effect between MoSSe and graphene, the adsorption energies of Li in heterostructures are much larger than those of pristine MoSSe and graphene. Accordingly, the MoSSe/G heterostructures achieve a high theoretical capacity of 560.59 mA h/g. Moreover, the diffusion barriers in SMoSe/G and SeMoS/G heterostructures are 0.17 and 0.22 eV, respectively, ensuring high mobility of Li. All these encouraging results demonstrate that the MoSSe/graphene heterostructures are high-performance anodes for advanced LIBs. Image 1 • A detailed investigation of MoSSe/G heterostructures as LIB anodes are carried out. • Improved electrical conductivity and mechanical stiffness are observed in the MoSSe/G heterostructures. • The MoSSe/G heterostructures possess a high specific capacity of 560.59 mA h/g and suitable open circuit voltage. • The diffusion barriers of SMoSe/G and SeMoS/G heterostructures are 0.17 and 0.22 eV, respectively. [ABSTRACT FROM AUTHOR]

• VS 2 /BlueP heterostructures as anodes could combine the advantages of VS 2 and BlueP. • Improved electrical conductivity and mechanical property are observed in the heterostructures. • VS 2 /BlueP heterostructures possess a high specific capacity of 1211.34 mA h/g. In this work, based on first principles calculations and molecular dynamics simulation, we systematically investigated the VS 2 /blue phosphorene (BlueP) heterostructures as potential anodes for LIBs. Our results show that both H-VS 2 /BlueP and T-VS 2 /BlueP heterostructures exhibit metallic characteristics, ensuring good electrical conductivity for the fast electron transport. The Young's moduli (187.3 N/m for H-VS 2 /BlueP and 183.4 N/m for T-VS 2 /BlueP), mechanical flexibility (ultimate strains > 16%) and adsorption energy of VS 2 /BlueP heterostructures are remarkably improved in comparison with pristine BlueP. Such improved mechanical property and adsorption energy are of great significance to suppress the anode pulverization on the whole lithium intercalation–deintercalation process. Moreover, the specific capacities of VS 2 /BlueP heterostructures are up to 1211.34 mA h/g (multi-layer Li adsorption), which are much higher than pristine BlueP and commercial graphite anodes. In addition, diffusion barriers in the H-VS 2 /BlueP and T-VS 2 /BlueP heterostructures are 0.17, 0.16 eV, respectively, implying high mobility of Li. All these encouraging results indicate that VS 2 /BlueP heterostructures are promising anodes to achieve advanced LIBs. [ABSTRACT FROM AUTHOR]