Solid-State Fabrication of Co₃V₂O₈@C Anode Materials with Outstanding Rate Performance and Cycling Stability by Synergistic Effects of Pseudocapacity and Carbon Coating

Abstract

Pseudocapacitive materials can synergistically achieve the aim of both high energy as well as high-power density. However, the cycling stability is usually not satisfactory. To overcome this drawback, a carbon coating method is employed. Herein, we report a simple one-step method for the fabrication of Co 3 V 2 O 8 @C composite structures. Such Co 3 V 2 O 8 @C anode materials exhibit superior long cycle performance, which can deliver a discharge capacity of ∼835 mAh g −1 at a current density of 4.0 A g −1 for more than 500 cycles with a capacity retention of ∼100%. Moreover, a notable rate performance of 808, 712, 307, and 101 mAh g −1 under current densities of 5, 10, 20, and 30 A g −1 is also achieved, respectively. The experimental data clearly demonstrate that the intriguing electrochemical properties can be ascribed to the synergistic effects of pseudocapacity and carbon coating. To be specific, the pseudocapacity ensures the rate performance, while carbon coating ensures the cycling performance. This may pave the way for the development of lithium-ion batteries with high power and energy density. Moreover, this synthetic strategy can be an instructive precedent for fabricating ternary metal oxides with excellent electrochemical performance.

VN@C hollow structures derived from ZIF-8 templates for a lithium-ion battery anode

“…Pseudocapacitive materials can synergistically achieve the aim of high energy density and power density. 56,59 This could give a great explanation for the large specific capacity at high current density of the VN@C electrode. As the current density increases, the higher pseudocapacitive contribution will endow the active material with faster reaction kinetics, which is crucially important for the satisfying specific capacity under a current density of 1 A g −1 .…”

“…Using the following equations, eqn (2) and (3), the contributions of diffusion and surface capacitance to the capacity can be calculated for the as-synthesized electrode material. 56,57 i = av b log i = b log v + log a where a and b are constants, i is the current density and v is the scan rate. Eqn (3) is transformed from eqn (2).…”

“…Using the following equations, eqn ( 2) and ( 3), the contributions of diffusion and surface capacitance to the capacity can be calculated for the assynthesized electrode material. 56,57 i = av b…”

Construction of Cu2+-doped MnCO3 micro-rhombohedrons and micro-olives as promising anode materials for high performance lithium-ion batteries

“…Surface-limited capacitive-dominated processes can facilitate fast kinetics, which contributes to the high rate properties during the charge–discharge process. 27,29…”

“…Previous reports have demonstrated that high rate properties mean fast reaction kinetics. 26,27 In order to further analyze the fast electrochemical kinetics of MnCO 3 , CV curves of the Cu 2+ -doped rhombohedral MnCO 3 microparticle electrode at a slower scan rate were recorded (Fig. 10a).…”