Electrochemical properties of yolk-shell structured ZnFe2O4 powders prepared by a simple spray drying process as anode material for lithium-ion battery

Abstract

ZnFe2O4 yolk–shell powders were prepared by applying a simple spray-drying process. Dextrin was used as a drying additive and carbon source material, and thus played a key role in the preparation of the powders. The combustion of precursor powders consisting of zinc and iron salts and dextrin obtained by a spray-drying process produced the yolk–shell-structured ZnFe2O4 powders even at a low post-treatment temperature of 350°C. The ZnFe2O4 powders prepared from the spray solution without dextrin had a filled and pockmarked structure. The initial discharge capacities of the ZnFe2O4 yolk–shell and filled powders post-treated at 450°C at a current density of 500 mA g−1 were 1226 and 993 mA h g−1, respectively, and the corresponding initial Coulombic efficiencies were 74 and 58%. The discharge capacities of the ZnFe2O4 powders with yolk–shell and filled structures post-treated at 450°C after 200 cycles were 862 and 332 mA h g−1, respectively. The ZnFe2O4 yolk–shell powders with high structural stability during cycling had superior electrochemical properties to those of the powders with filled structure.

One-pot synthesis of core–shell-structured tin oxide–carbon composite powders by spray pyrolysis for use as anode materials in Li-ion batteries

“…The SnO x -carbon composite powders had a stable discharge capacity of about 870 mA h g -1 from around 50 to 200 cycles. The slight increase in the discharge capacity of the SnO x -carbon composite powder above 200 cycles was likely due to the observed formation of polymeric gel-like film over the powder [30]. On the other hand, the discharge capacities of the bare SnO 2 powders decreased continuously to the 145 mA h g -1 after 200 cycles.…”

Phase-pure β-NiMoO4 yolk-shell spheres for high-performance anode materials in lithium-ion batteries

“…The slope of NM-800-S after the 100th cycle was significantly lower than that of NM-800, which reveals the high lithium-ion diffusion rate of the yolk-shell-structured powder [9]. Thus, the NM-800-S of the yolk-shell-structured NiMoO 4 b-phase can be a promising anode material for LIBs, demonstrating the good electrochemical properties with long cycle performance.…”

“…However, the NM-800-S specimen with yolk-shell structure contained an abundant volume of pores with sizes ranging between 3 and 4 nm, indicating that the pores of NM-800-S are highly uniform with a narrow pore size distribution. These abundant mesopores in NM-800-S powders lead to a large surface area, which can provide fast diffusion paths for lithium ions during the charge-discharge reaction, and thus, the electrode properties would be enhanced [9,37,38]. The pore-size distributions of the four samples analyzed further using mercury porosimetry (Fig.…”

“…Although graphite anodes have been widely used because of their high stability, reversibility, and low cost, they exhibit a relatively low maximum capacity of 371 mA h g À1 because a single lithium ion is intercalated into up to six carbon atoms [1][2][3][4][5]. Thus, new electrode materials with high specific capacities and long cycle life, such as transition metal oxides, are being considered as viable alternatives for next-generation anode materials [6][7][8][9][10][11][12][13][14].…”

“…However, the capacity retentions of the a/b-NiMoO 4 thin film and nanowire were below 50% after 40 and 20 cycles, respectively. The nanocrystalline metal oxides having a yolk-shell structure with high specific surface areas have many advantages in LIB applications as compared to their bulk counterparts, such as enhanced electrochemical properties even at high current densities and a faster charge-discharge reaction [9,[26][27][28][29][30][31][32][33][34]. The yolk-shell structures also result in long cycle life because of their distinctive core/void/shell configuration, offering free space to accommodate the volume change during the lithium insertion and desertion processes.…”