Selective Formation of Carbon‐Coated, Metastable Amorphous ZnSnO₃ Nanocubes Containing Mesopores for Use as High‐Capacity Lithium‐Ion Battery

Abstract

Mesoporous and amorphous ZnSnO3 nanocubes of ~37 nm size coated with a thin porous carbon layer have been prepared using monodisperse ZnSn(OH)6 as the active precursor and low-temperature synthesized polydopamine as the carbon precursor. The small single nanocubes cross-link with each other to form a continuous conductive framework and interconnected porous channels with macropores of 74 nm width. Because of its multi-featured nanostructure, this material exhibits greatly enhanced integration of reversible alloying/de-alloying (i.e., transformation of Li(4.4)Sn and LiZn to Sn and Zn) and conversion (i.e., oxidation of Sn and Zn to ZnSnO3) reaction processes with an extremely high capacity of 1060 mA h g(-1) for up to 100 cycles. A high reversible capacity of 650 and 380 mA h g(-1) can also be delivered at rates of 2 and 3 A g(-1), respectively. This excellent electrochemical performance is attributed to the small particle size, well-developed mesoporosity, the amorphous nature of the ZnSnO3 and the continuous conductive framework produced by the interconnected carbon layers.

Tailoring the shape of amorphous nanomaterials: recent developments and applications

“…In this regard, it seems very difficult for amorphous nanomaterials to present as polyhedra. Nevertheless, a small number of notable examples demonstrate the very recent progress in the fabrication of polyhedral amorphous nanostructures by some innovative methods [79][80][81][82][83][84].…”

“…11. Following a similar route, Lu's group [84] prepared mesoporous and amorphous ZnSnO 3 nanocubes with a size of ~37 nm coated with a thin porous carbon layer using ZnSn(OH) 6 as the active precursor and polydopamine as the carbon precursor. They found that these small single nanocubes would crosslink with each other to form a continuous conductive framework containing interconnected channels with macropores with a width of 74 nm.…”

“…As a result, large irreversible capacity losses are typically observed during lithiation/delithiation because anisotropic volume swelling and contraction cause pulverization of the Si and loss of electrical contact with the current collector. Amorphous materials are expected to have smaller and more homogeneous volume expansion than crystalline ones, as well as being effective at releasing volume strain because of their intrinsically isotropic nature [51,84]. Therefore, nanosized amorphous materials should have better cycling performance during the discharge/charge process than bulk crystalline ones.…”

“…The large number of under-coordinated atoms (good electron acceptors) and reactive sites at the surface means that amorphous materials also have the advantage over crystalline ones in their contact with the electrolyte and active substances (electron donors), which favors electrochemical processes. In regard to the merits discussed above, amorphous nanomaterials have already demonstrated their superior performance over bulk crystalline materials in various electrochemical applications, including lithium-and/or sodium-ion batteries [51,62,66,71,79,84,[96][97][98][99][100], super-or pseudo-capacitors [77,78,83], electrochemical water splitting [59] and sensors [72,81]. The amorphous CoSnO 3 @C nanoboxes reported by Wang et al [79] showed high initial discharge and charge capacities of around 1,410 and 480 mA h g −1 , respectively, as revealed in Fig.…”

“…Because of their complex internal structure, the growth of amorphous nanomaterial is usually ruleless, resulting in irregular particles using solution approaches or thin films using deposition techniques as their conventional shape. Over the last decade, inorganic amorphous nanomaterials with a variety of novel shapes, with notable examples including spheres, wires, tubes, fibers, cubes, octahedra, polyhedra, flower-like spheres and arrays, which are summarized in spheres (hollow) CaCO 3 gas-diffusion solution method [43] spheres CaCO 3 solution method [44] spheres CaCO 3 solution method [45] spheres CaCO 3 solution method [46] spheres CaCO 3 solution method [47] spheres Si thermal decomposition [48] spheres Si solution method [49] spheres Si/Ti solution method [50] spheres Si:H thermal decomposition [51] spheres Si:H thermal decomposition [52] spheres Se solution method [53] spheres TiO 2 solution method [54][55][56] spheres (hollow) PbO-TiO 2 sol-gel method [57] spheres Co-B alloy solution method [58] spheres 2 solution method [80] nanoboxes Ni(OH) 2 solution method [81] nanocubes (hollow) Co(OH) 2 solution method [82] nanopolyhedra (hollow) CoS solution method [83] mesopores nanocubes ZnSnO 3 solution method and annealing [84] REVIEWS SCIENCE CHINA Materials Table 1, have been synthesized. In this review, we explain how these exquisite nanostructures can be obtained by a number of innovative methods.…”