One‐Pot Facile Synthesis of Double‐Shelled SnO₂ Yolk‐Shell‐Structured Powders by Continuous Process as Anode Materials for Li‐ion Batteries

Abstract

Hollow and yolk-shell metal oxide powders used as energy storage materials exhibit good electrochemical properties at high current density because of their shortened diffusion length and increased amount of contact area between the electrolyte and the electrode for Li + insertion/extraction. Although various types of hollow-structured oxide materials have been studied as anode and cathode electrode materials for lithium secondary batteries, [13][14][15][16][17][18][19][20][21][22][23][24][25] the hollow-structured powders cannot be readily applied as battery materials because of their low energy densities due to low tab density. The disadvantages of the hollow materials can be overcome using core@void@shellconfi gured yolk-shell-structured powder particles. The core of such yolk-shell-structured powder particles will improve the rate capability as well as the energy density of the powders by increasing the weight fraction of the electrochemically active component. [ 12 , 15 ] The structures of the metal oxides that undergo large changes in volume during Li + insertion/extraction strongly affect the electrochemical properties of the anodes produced using such materials. The voids between the yolk and the shell can also serve as a buffering space for the electroactive core material during lithium insertion and extraction; therefore, various types of yolk-shell-structured metal oxides prepared using hydrothermal, coprecipitation, and shell-by-shell deposition methods have previously been studied as anode electrode materials. [ 1-7 , 9-14 ] According to previous reports, the yolk-shell-structured powders were mainly prepared using a multistep solution method; [ 1-10 , 12-14 , 27-37 ] therefore, a scalable one-pot method should be developed for the large-scale production of yolk-shellstructured powders. We report a novel, simple one-pot method of systematically synthesizing double-shelled yolk-shell-structured powders by scalable spray pyrolysis, which is one of the gas phase reaction methods. The electrochemical properties of yolk-shell-structured SnO 2 powders prepared using the hydrothermal method have previously been well studied. [3][4][5] Therefore, in this study, SnO 2 was selected as the fi rst target material to develop the yolk-shell-structured powders with spray pyrolysis. The mechanism of the formation of the double-shelled SnO 2 yolk-shell-structured powders in spray pyrolysis was investigated.The morphologies and dot-mapping images of the SnO 2 powder particles directly prepared using spray pyrolysis are shown in Figure 1 . The SEM and TEM images show that the powder particles of all sizes exhibit uniform yolk-shell structures. Mobile spherical core powder is located inside the uniformly thick spherical shell, as shown in the SEM image in the insert of Figure 1 a. The HR-TEM images of the powder particles, as shown in Figure 1 c, reveal the double-shelled yolkshell structure of the particles. The dot mappings for the Sn and O components, as shown in Figure 1 e, are consistent with the double-shelle...

Fabrication of NiFe2O4/C hollow spheres constructed by mesoporous nanospheres for high-performance lithium-ion batteries

“…Recently, various transition metal oxides such as Co 3 O 4 [2][3][4][5], Fe 2 O 3 [6][7][8][9][10], Fe 3 O 4 [11], SnO 2 [12][13][14][15], CoMn 2 O 4 [16], NiCo 2 O 4 [17][18][19], MnFe 2 O 4 [20,21], NiFe 2 O 4 [22][23][24][25] and etc. have been considered as the alternative high-performance anode materials for LIBs due to their much higher theoretical capacity than that of commercial graphite.…”

One-step synthesis of Li-doped NiO as high-performance anode material for lithium ion batteries

“…Transition metal oxides (TMOs), such as CoO x [12][13][14][15][16][17], CuO [18][19][20][21][22], SnOx [23][24][25], MnOx [26,27], CoMn 2 O 4 [28,29], ZnMn 2 O 4 [30] and MnCo 2 O 4 [31], have been widely studied as promising alternative anode materials for replacing the graphite used in LIBs for their high theoretical capacities. In particular, NiO is one of the promising anode materials for Li ion batteries because of its low cost and environmental friendless [32][33][34][35][36][37].…”

Electrochemical Properties of Yolk–Shell‐Structured CuO–Fe2O3 Powders with Various Cu/Fe Molar Ratios Prepared by One‐Pot Spray Pyrolysis

“…Combustion, contraction, and recombustion processes occurred in a step-by-step manner as the CuO-Fe 2 O 3 -carbon composite intermediate progressed through the reactor, finally producing yolk-shell-structured CuO-Fe 2 O 3 powders irrespective of compositions. [22][23][24] Heat evolved from the combustion of carbon resulted in the crystalline CuO-Fe 2 O 3 powders with uniform composition. The compositions of the yolkshell CuO-Fe 2 O 3 powders were analyzed by inductively coupled plasma-optical emission spectrometry (ICP-OES, Table S1, the Supporting Information).…”

“…[18][19][20][21][22][23][24][25][26][27] Recently, a simple spray pyrolysis process was successfully applied to the preparation of yolk-shell-structured powders. [22][23][24] Using this one-pot spray pyrolysis process, materials with single, binary, ternary, quaternary, and quinary yolkshell structures were successfully produced under the same preparation conditions. [24] The electrochemical properties of the yolk-shell-structured materials with single and binary metal oxides prepared by spray pyrolysis were mainly investigated.…”