Hybridizing nanostructured metal oxides with multiwalled carbon nanotubes (MWCNTs) is highly desirable for the improvement of electrochemical performance of lithium-ion batteries. Here, a facile and scalable strategy to fabricate hierarchical porous MWCNTs/Co3O4 nanocomposites has been reported, with the help of a morphology-maintained annealing treatment of carbon nanotubes inserted metal organic frameworks (MOFs). The designed MWCNTs/Co3O4 integrates the high theoretical capacity of Co3O4 and excellent conductivity as well as strong mechanical/chemical stability of MWCNTs. When tested as anode materials for lithium-ion batteries, the nanocomposite displays a high reversible capacity of 813 mAh g(-1) at a current density of 100 mA g(-1) after 100 charge-discharge cycles. Even at 1000 mA g(-1), a stable capacity as high as 514 mAh g(-1) could be maintained. The improved reversible capacity, excellent cycling stability, and good rate capability of MWCNTs/Co3O4 can be attributed to the hierarchical porous structure and the synergistic effect between Co3O4 and MWCNTs. Furthermore, owing to this versatile strategy, binary metal oxides MWCNTs/ZnCo2O4 could also be synthesized as promising anode materials for advanced lithium-ion batteries.

Application of transition metal phosphides (TMPs) for electrochemical energy conversion and storage has great potential to alleviate the energy crisis. Although there are many methods to get TMPs, it is still immensely challenging to fabricate hierarchical porous TMPs with superior electrochemical performances by a simple, green, and secure approach. Herein, we report a facile method to synthesize the CoP/C nanoboxes by pyrolysis of phytic acid (PA) cross-linked Co complexes that are acquired from reaction of PA and ZIF-67. The PA can not only slowly etch ZIF-67 and gain a hollow structure but also act as a source of phosphorus to prepare CoP/C nanoboxes. The CoP/C nanoboxes deliver an ultrahigh specific capacity (868 mA h g −1 at 100 mA g −1 ) and excellent cycle stability (523 mA h g −1 after 1000 cycles at 500 mA h g −1 ) when used as anode materials for lithium-ion batteries. Moreover, when used as an electrocatalyst for hydrogen evolution reaction, the CoP/C nanoboxes exhibit ultralow overpotential, small Tafel slope, and excellent durability in acidic media.

In this study, an in situ growth method is developed for the partial conversion of current collector into active materials for lithium ion batteries (LIBs). Through thermal treatment of a metal–organic framework (MOF) precursor, of which the metal ion is provided by a Cu foil current collector, porous CuO nanorod arrays (NRAs) can be directly formed on Cu foil. Importantly, this strategy can avoid the poor contact problem between the current collector and electrode material as well as circumvent the addition of insulating material (binder) and inhomogeneous distribution of conductive carbon material and active material on the current collector. When evaluated as binder-free electrodes for LIBs, porous CuO NRAs deliver a high specific capacity (1341 mA h g–1 at 100 mA g–1) and enhanced rate capability and cycling ability (671 mA h g–1 at 100 mA g–1 after 150 cycles).

SnO2 has been considered as a promising anode material for lithium‐ion batteries (LIBs) and sodium ion batteries (SIBs), but challenging as well for the low‐reversible conversion reaction and coulombic efficiency. To address these issues, herein, SnO2 quantum dots (≈5 nm) embedded in porous N‐doped carbon matrix (SnO2/NC) are developed via a hydrothermal step combined with a self‐polymerization process at room temperature. The ultrasmall size in quantum dots can greatly shorten the ion diffusion distance and lower the internal strain, improving the conversion reaction efficiency and coulombic efficiency. The rich mesopores/micropores and highly conductive N‐doped carbon matrix can further enhance the overall conductivity and buffer effect of the composite. As a result, the optimized SnO2/NC‐2 composite for LIBs exhibits a high coulombic efficiency of 72.9%, a high discharge capacity of 1255.2 mAh g−1 at 0.1 A g−1 after 100 cycles and a long life‐span with a capacity of 753 mAh g−1 after 1500 cycles at 1 A g−1. The SnO2/NC‐2 composite also displays excellent performance for SIBs, delivering a superior discharge capacity of 212.6 mAh g−1 at 1 A g−1 after 3000 cycles. These excellent results can be of visible significance for the size effect of the uniform quantum dots.