•Ce-doped α-FeOOH was synthesized by a hydrothermal method followed acid-treatment.•Ce-doped α-FeOOH for LIBs exhibits 830 mA h g−1 at after 800 cycles.•Ce-doped α-FeOOH for SIBs exhibits an initial capacity of 587 mA h g−1.•Ce-doping reduced the polarization of electrode and promoted cycling performance.Ce-doped α-FeOOH nanorods with high yields were conveniently prepared by a hydrothermal method followed by an acid-treatment process. It is found that Ce uniformly distributes in the α-FeOOH nanorod nanostructures through elemental mapping analysis. The 0.5 wt% Ce-doped α-FeOOH electrode displayed excellent cycling performance with a high discharge capacity of 830 mA h g−1 after 800 charge/discharge cycles at a high current of 2000 mA g−1. The enhanced electrochemical performance can be attributed to the improved electronic conductivity, Li-ion diffusion kinetics and structure stability after Ce doping. Furthermore, a 0.5 wt% Ce-doped α-FeOOH//LiFePO4 lithium ion cell with an initial discharge capacity of 580 mA h g−1 at 1000 mA g−1 based on the total weight of the anode material has been fabricated for the first time. The obtained 0.5 wt% Ce-doped α-FeOOH electrode as anode material for sodium-ion batteries also exhibits a high initial discharge capacity of 587 mA h g−1 at 100 mA g−1.Proper contents of Ce doping in α-FeOOH nanorods have been conveniently fabricated with high yields through a hydrothermal followed an acid-washing method. The 0.5 wt% Ce-doped α-FeOOH suppressed the dramatic drop of specific discharge capacity within the first 100 cycles and exhibits excellent long-term cycling performances (830 mA h g−1 at high current densities of 2000 mA g−1 after 800 cycles). The 0.5 wt% Ce-doped α-FeOOH//LiFePO4 full cell exhibits the initial discharge capacity of ∼580 mA h g−1 at 1000 mA g−1. The excellent performances of the obtained products reveal potential applications as anode for Lithium-ion batteries. When utilized as anode material for Sodium-ion batteries, it exhibits an initial discharge capacity of 587 mA h g−1 at 100 mA g−1. The 0.5 wt% Ce-doped α-FeOOH nanorod could be applied as a highly attractive candidate for energy storage applications that have environmental friendly, low cost and reliability requests.

Porous electrode materials with both high rate capabilities and long cycle lives are significant to satisfy the urgent demand of energy storage. Furthermore, a one dimensional structure can facilitate Li+ diffusion and accommodate the volume expansion. Here, porous MnFe2O4 microrods have been successfully synthesized by a room temperature reaction and then moderate annealing in an Ar atmosphere. The porous MnFe2O4 electrodes exhibit high reversible capacity and outstanding cycling stability (after 1000 cycles still maitain about 630 mA h g−1 at the current density of 1 A g−1), as well as high coulombic efficiency (>98%). Moreover, even at a high current density of 4 A g−1, the porous MnFe2O4 microrods can still maintain a reversible capacity of 420 mA h g−1. These results demonstrate that the porous MnFe2O4 microrods are promising anode materials for high performance Li-ion batteries.

The design of hierarchical nanostructures to be used as anodes (involving higher rate capabilities and better cycle lives) and meet further lithium ion battery applications has attracted wide attention. Herein, a hierarchical MnO2@NiO core–shell nanostructure with a MnO2 nanorod as the core and NiO flakes as the shell has been synthesized by combining a hydrothermal treatment and an annealing process. MnO2 nanorods serve as a high theoretical capacity (1233 mA h g−1) material, and they allow efficient electrical and ionic transport owing to their one-dimensional structure. The porous NiO flakes used as the shell would enlarge the contact area across the electrode/electrolyte, and can also serve as volume spacers between neighboring MnO2 nanorods to maintain electrolyte penetration as well as reducing the aggregation during Li+ insertion/extraction. As a result, the MnO2@NiO core–shell structure exhibits improved cycling stability (939 mA h g−1 after 200 cycles at a current density of 1 A g−1) and outstanding rate performance, suggesting that the synergetic effect and characteristics of the core–shell nanostructure would benefit the electrochemical performance of lithium ion batteries.

Rationally designed nanocomposites with effective surface modification are important to improve the electrochemical performance of Li-ion batteries. Carbon coatings as an economical and practically feasible approach, which would provide good conductivity and promote Li-ion diffusion, leading to improved electrochemical performance. Mn3O4@C core–shell nanorods were prepared using the synchronous reduction and decomposition of acetylene. The resulting Mn3O4@C core–shell nanorods possess a one dimensional shape, porous structure and uniform carbon layer (∼3 nm), which result in electrochemical stability. When tested as anodes, they deliver a specific capacity of 765 mA h g−1 after 100 cycles at a current density of 500 mA g−1, which is considerably higher than pure Mn3O4 nanorods. Even at a current density of 2 A g−1, the Mn3O4@C core–shell nanorods can maintain 380 mA h g−1. Their excellent lithium storage performance can be ascribed to the uniform carbon coating layer as well as their unique one dimensional porous structure.

CuFe2O4 network, prepared via the electrostatic spray deposition technique, with high reversible capacity and long cycle lifetime for lithium ion battery anode material has been reported. The reversible capacity can be further enhanced by coating high electronic conductive polypyrrole (PPy). At the current density of 100 mA·g−1, Li/CuFe2O4 electrode delivers a reversible capacity of 842.9 mAh·g−1 while the reversible capacity of Li/PPy-coated CuFe2O4 electrode increases up to 1106.7 mAh·g−1. A high capacity of 640.7 mAh·g−1 for the Li/PPy-coated CuFe2O4 electrode is maintained in contrast of 398.9 mAh·g−1 for Li/CuFe2O4 electrode after 60 cycles, which demonstrates good electrochemical performance of the composite due to the increase of electronic conductivity. The electrochemical impedance spectroscopy (EIS) further reveals that the Li/PPy-coated CuFe2O4 electrode has a lower charge transfer resistance than the Li/CuFe2O4 electrode.CuFe2O4 network has been prepared via the electrostatic spray deposition technique. Following coating high electronic conductive polypyrrole (PPy) enhances the electrochemical performance.Download full-size image

Porous electrode materials with both high rate capabilities and long cycle lives are significant to satisfy the urgent demand of energy storage. Furthermore, a one dimensional structure can facilitate Li+ diffusion and accommodate the volume expansion. Here, porous MnFe2O4 microrods have been successfully synthesized by a room temperature reaction and then moderate annealing in an Ar atmosphere. The porous MnFe2O4 electrodes exhibit high reversible capacity and outstanding cycling stability (after 1000 cycles still maitain about 630 mA h g−1 at the current density of 1 A g−1), as well as high coulombic efficiency (>98%). Moreover, even at a high current density of 4 A g−1, the porous MnFe2O4 microrods can still maintain a reversible capacity of 420 mA h g−1. These results demonstrate that the porous MnFe2O4 microrods are promising anode materials for high performance Li-ion batteries.