Pineapple-shaped ZnCo₂O₄ microspheres as anode materials for lithium ion batteries with prominent rate performance

Abstract

Pineapple-shaped ZnCo 2 O 4 (ZCO) microspheres with a porous nanostructure are synthesized by a typical hydrothermal method and used as high performance anodes in Li-ion batteries. The microspheres show excellent cycling and rate performance. The initial discharge capacity of 1596.2 mA h g À1 and the reversible discharge capacity of 1132 mA h g À1 can be maintained after 120 cycles at a current density of 100 mA g À1 . More interestingly, the reversible capacity as high as 800 mA h g À1 can be retained at a high current density of 1000 mA g À1 after 200 cycles. Surprisingly, the pineapple-shaped ZCO electrode exhibits a prominent rate performance, a reversible specific capacity of 1237 mA h g À1 and 505 mA h g À1 at current densities of 500 mA g À1 and 6000 mA g À1 respectively. In addition, the influence of distilled water and urea on the phase and morphology of the material is investigated by SEM and EDS. The results indicate that adding distilled water into the solvent could ensure the high purity of products with no loss of the Zn element. At the same time, the cycle performance can be effectively improved because of the more regular surface and the more stable structure of the microspheres with urea-assistance.

PVP assisted morphology-controlled synthesis of hierarchical mesoporous ZnCo 2 O 4 nanoparticles for high-performance pseudocapacitor

“…Additionally, as shown in all FE-SEM images, the numerous pores appeared on the surface of each sample maybe attributed on release of gaseous species during the annealing process. These pores will not only provide a larger contact area between the active materials and electrolytes but will also give an excellent electrical conductivity with shorter transport/diffusion path where electrons can pass through and move easily that will result to a lesser resistance; these are highly desired characteristics of advanced electrode for electrochemical storage applications [29].…”

“…Due to a larger surface area, P2 sample has more locations and channels providing a larger contact area between the active materials and electrolytes. Additionally, the bigger pore volume of P2 sample would promote the efficient diffusion of electrolyte into the active material with less resistance and can buffer the volume expansion during the discharge/charge process [29]. With this advantage, the synthesized ZnCo 2 O 4 NPs with ring-like morphology is expected to have a better electrochemical performance results.…”

Design and synthesis of hollow NiCo2O4 nanoboxes as anodes for lithium-ion and sodium-ion batteries

“…This over-theoretical value phenomenon for the NCO-NBs electrode can be explained as follows: Firstly, the increasing specific capacity may be owing to the reversible formation/decomposition of an organic polymeric gel-like film. 17 Secondly, the improvement in storage capability can be explained by the pseudo-capacitive interfacial storage reaction, which may arise from under-potential deposition and lithium storage by reaction with the grain boundary phase in polycrystalline materials. 50,51 Besides the good specific capacity and excellent cyclability, the rate capability of the Co 3 O 4 -NBs and NCO-NBs was evaluated at various current densities from 500 to 8000 mA g -1 as presented in the Fig 6d. As it can be seen, it shows good rate capability with the average discharge capacities of 1129, 950, 919, 846 and 739 mA h g -1 at 500, 1000, 2000, 4000 and 6000 mA g -1 .…”

Three-dimensional NiCo2O4 nanowire arrays: preparation and storage behavior for flexible lithium-ion and sodium-ion batteries with improved electrochemical performance

“…Based on the previous reports, the entire electrochemical process for the both electrodes can be expressed as follows: [12][13][14][15][16][17] …”