Template‐Assisted Synthesis of Honeycomb‐Like CoFe₂O₄/CNTs/rGO Composite as Anode Material for Li/Na‐Ion Batteries

Abstract

CoFe2O4 is a fascinating anode material due to its high theoretical capacity. However, the low electronic conductivity, limited electrochemical kinetics and huge volume expansion lead to poor electrochemical performance. Here, the CoFe2O4/CNTs/rGO ternary composite with a honeycomb‐like structure (PS‐CFO/CNTs/rGO) has been synthesized via a spray drying method assisted by polystyrene (PS) soft template. The rational 3D porous structure design not only enhances the transport capacity of Li/Na ions, but also provides buffer spaces for alleviating volume expansion, resulting in rapid electrochemical kinetics and improved electrode integrity during cycling. In particular, to improve the electrochemical performance, a facile pre‐treatment process combining heat‐treatment and pre‐sodiation treatment is first developed for the anode materials of sodium‐ion batteries (SIBs). As a result, at 1 A g−1 after 365 cycles, the pronounced capacity of PS‐CFO/CNTs/rGO composite can be maintained at 750 mAh g−1 for lithium‐ion batteries (LIBs), and after 5000 cycles, maintained at 195 mAh g−1 for the SIBs.

Molten salt synthesis of disordered spinel CoFe2O4 with improved electrochemical performance for sodium-ion batteries

“…In the anodic process, the oxidation peaks at 0.8 and 1.2 V are attributed to the reformation of CoFe 2 O 4 via the oxidation of Fe 0 and Co 0 to Fe 3+ and Co 2+ , respectively. 69,70 All the CV curves almost overlapped during the subsequent cycle, indicating high reversibility of the electrochemical reaction. 33,71 The selected cycles of the charge and discharge profiles for all electrodes at a current density of 0.1 A g −1 is shown in Fig.…”

Oxygen‐Vacancy‐Abundant Ferrites on N‐Doped Carbon Nanosheets as High‐Performance Li‐Ion Battery Anodes

“…In the first cathodic scan, the peaks at 1.42 and 0.51 V are ascribed to the reduction of CoFe 2 O 4 to metallic Co and Fe, and the peaks shift to 1.41 and 0.81 Vi nt he subsequent cycles. [54,55] In the anodic process, the broad peak at 1.63 Vi s relatedt ot he oxidation of Co and Fe to CoO and Fe 2 O 3 ,r espectively. [11] Figure 7b displays the discharge/charge curves for the first three cycles of NC@CoFe 2 O 4 at ac urrent density of 200 mA g À1 .T he initial dischargea nd chargec apacities of NC@CoFe 2 O 4 are 1600 and 1084 mA hg À1 ,w hich are much highert han those of CoFe 2 O 4 (1111 and 740 mA hg À1 ,F igure S5 b, Supporting Information) and Fe 2 O 3 (1087 and 638 mA hg À1 ,F igure S5 d, Supporting Information).…”

Mulberry‐Like Core‐Shell Structured C@MnO2 as Electrode Material for Li–Ion Batteries and Pseudo‐Capacitors

“…MnO 2 has high theoretical capacity for both these devices (Li ion batteries anode material: 1233 mAh g À 1 ; pseudo-capacitor electrode material: over 1100F g À 1 ) and is also highly abundant, eco-friendly, low cost and non-toxic, which makes it one of the most attractive potential alternatives. [3][4][5][6][7][8] However, like most of the oxide electrode, [9,10] problems such as low capacity, poor rate performance and pulverization resulted from low intrinsic electronic conductivity (10 À 5 ∼ 10 À 6 S cm À 1 ), [11] hindering its application. [12] Besides, rapid capacity decay due to huge volume change is also a problem as Li-ion batteries anode material.…”