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Heterostructured materials show great potential to enhance the specific capacity, rate performance and cycling lifespan of lithium-ion batteries owing to their unique interfaces, robust architectures, and synergistic effects. Herein, a polypyrrole (PPy)-coated nanotube-like Mo3S4/CoMo2S4 heterostructure is prepared by the hydrothermal and subsequent in situ polymerization methods. The well-designed nanotube-like structure is beneficial to relieve the serious volume changes and facilitate the infiltration of electrolytes during the charge/discharge process. The Mo3S4/CoMo2S4 heterostructure could effectively enhance the electrical conductivity and Li+ transport kinetics owing to the refined energy band structure and the internal electric field at the heterostructure interface. Moreover, the conductive PPy-coated layer could inhibit the obvious volume expansion like a firm armor and further avoid the pulverization of the active material and aggregation of generated products. Benefiting from the synergistic effects of the well-designed heterostructure and PPy-coated nanotube-like architecture, the prepared Mo3S4/CoMo2S4 heterostructure delivers high reversible capacity (1251.3 mAh g−1 at 300 mA g−1), superior rate performance (340.3 mAh g−1 at 5.0 A g−1) and excellent cycling lifespan (744.1 mAh g−1 after 600 cycles at a current density of 2.0 A g−1). Such a design concept provides a promising strategy towards heterostructure materials to enhance their lithium storage performances and boost their practical applications. [ABSTRACT FROM AUTHOR]

A sandwich-like SC@EG was prepared by a simple mixing of CLRA and EGO via strong covalent bonds. The robust covalent interaction helped maintain the stability of the anode electrode materials during charge/discharge cycles, resulting in remarkable cycling performance. The synergistic effect between SC and EG led to improvements in conductivity, porous structure, and defect degree compared to SC, resulting in the high irreversible capacity and rate performance of SC@EG. [Display omitted] • The sandwich-like SC@EG composite was designed and prepared. • SC@EG owned orderly layer-by-layer stacking structure with suitable pores. • For LIBs, SC@EG exhibited excellent rate performance (172 mAh g−1 at 4 A g−1) • For KIBs, SC@EG delivered a high reversible capacity of 268 mAh g−1 at 0.1 A g−1. • SC@EG revealed good cyclic stability in LIBs and KIBs. This study investigated the use of asphaltene from coal liquefaction residue (CLRA) as a precursor for creating carbon nanosheets, which were then used to create a unique sandwich structure of soft carbon (SC) coated with expanded graphite (EG) composite (SC@EG) anodes for both lithium-ion and potassium-ion batteries. The SC@EG was formed through a covalent bond between EG and SC, resulting in a porous structure with favorable porosity and copious defects that expedited the migration of both Li+ and K+ ions. The SC@EG showed good electrochemical properties including high reversible capacity (510 mAh/g at 0.5 A/g in LIBs and 268 mAh/g at 0.1 A/g in KIBs), good rate performance (172 mAh/g at 4 A/g in LIBs and 154 mAh/g at 1 A/g in KIBs) and cyclic stability, attributed to the exceptional electronic conductivity and profound porosity of the structure. [ABSTRACT FROM AUTHOR]

[Display omitted] • ZnFe 2 O 4 nanoparticles were prepared using Fe 2 O 3 /ZIF-8 as precursor. • Appropriate amount of Fe 2 O 3 leads to ZnFe 2 O 4 nanoparticles with porous structure. • Bimetallic ZnFe 2 O 4 nanoparticles exhibit good electrical conductivity. • The porous structure increases the contact area between ZnFe 2 O 4 and electrolyte. • ZnFe 2 O 4 nanoparticles exhibit enhanced lithium storage performance. ZnFe 2 O 4 nanoparticles and ZnO/ZnFe 2 O 4 composites were prepared by simple calcination of Fe 2 O 3 /ZIF-8. The bimetallic ZnFe 2 O 4 not only inherit the high lithium storage capacity of Fe 2 O 3 , but also exhibit higher conductivity than that of single Fe or Zn oxides. The effect of Fe 2 O 3 content in the raw materials on the structure and electrochemical performance of the product was discussed. Appropriate amount of Fe 2 O 3 helps to obtain ZnFe 2 O 4 nanoparticles with small size and porous structure, which can shorten the diffusion path of lithium ions, increase the contact area between the electrode material and electrolyte, thus improving the performance of the material. After 200 cycles at a current density of 300 mA g−1, the specific capacity can reach 1223.2 mAh/g. When the current density is increased to 2 A/g, the discharge specific capacity is retained at 809.4 mAh/g after 500 cycles. [ABSTRACT FROM AUTHOR]

• Porous nitrogen-doped carbon nanosheets (NC) is synthesized by calcining HMT-Zn. • FeMoO 4 @NC is synthesized by hydrothermal method. • NC can buffer the volume changes and provide a large amount of active sites. • FeMoO 4 @NC exhibits enhanced cycling stability and lithium storage performance. FeMoO 4 is a potential anode material for Li-ion batteries due to its high theoretical specific capacity. The factors that restrict the application of FeMoO 4 are the low specific surface area of the material and poor cycle stability caused by the huge volume change during the cycling process of lithium ion insertion and extraction. In this work, N -doped porous carbon was synthesized and composited with FeMoO 4 by a hydrothermal method. The large specific surface area provided by the porous structure can enable sufficient contact of ions/electrons with active sites, thereby enhancing the lithium storage performance and buffering the volume change during lithiation/delithiation, leading to a high cycling stability of the material. After 200 cycles at a current density of 300 mA g−1, the discharge specific capacity of the composite can reach up to 1291.4 mA h g−1. [ABSTRACT FROM AUTHOR]

The ultrathin porous CoO/Co 3 O 4 nanoribbons with oxygen vacancies were fabricated by a facile hydrothermal and annealing methodology. When used as anode electrode for lithium-ion battery, it exhibits good electrochemical performance by virtue of the 3D open mesoporous/macroporous structure and the existence of oxygen vacancies. [Display omitted] • The peony-like self-assembly ultrathin CoO/Co 3 O 4 nanoribbons was designed and prepared. • CoO/Co 3 O 4 nanoribbons owned unique structure with mesoporous/macroporous and oxygen vacancies. • CoO/Co 3 O 4 nanoribbons delivered a high reversible capacity of 544 mAh g−1 even after 500 cycles at 5 A g−1. • CNTs/Co 3 O 4 p-NRs revealed a superior rate performance. The efficient and stable lithium-ion batteries have inspired extensive interest; however, formidable anode electrode materials still remain a challenge. Herein, porous CoO/Co 3 O 4 nanoribbons were fabricated by a facile hydrothermal and annealing route. The self-assemble ultrathin CoO/Co 3 O 4 nanoribbons are formed by connected nano-worms with mesoporous/macroporous structure and oxygen vacancy. The porous ultrathin CoO/Co 3 O 4 nanoribbons benefit from buffering the volume change and enlarging the contact area between electrode and electrolyte, leading to long cycling life and high specific capacity. Furthermore, oxygen vacancies and a three-dimensional network enhance the internal conductivity and accelerate the diffusion of electrons/ions, resulting in excellent rate performance. The highest discharge capacity (957 mAh/g after 200 cycles at 0.5 A/g) and excellent rate capability (847 mAh/g at 5 A/g) are observed. Thus, these unique characteristics pave the way for CoO/Co 3 O 4 nanoribbons as suitable electrode materials for lithium storage devices. [ABSTRACT FROM AUTHOR]