Investigation of the Enhanced Lithium Battery Storage in a Polyoxometalate Model: From Solid Spheres to Hollow Balls

Abstract

Materials with hollow structures are generally considered more conducive to lithium‐ion storage than solid materials, but there is no suitable crystal model system to illustrate it. Herein, it is successfully simulated by utilizing polyoxometalate models to compare the lithium‐ion battery performances. New crystals, EMI‐PMo12 (EMI: 1‐ethyl‐3‐methylimidazolium) with solid sphere and EMI‐Mo72V30 and EMI‐Mo132 with hollow structures, are synthesized. In order to increase their electronic conductivity, the composites EMI‐PMo12@rGO, EMI‐Mo72V30@rGO, and EMI‐Mo132@rGO (rGO: reduced graphene oxide) can be prepared by introducing rGO. The composite EMI‐Mo72V30@rGO delivers a reversible capacity of 1145 mAh g−1 at 100 mA g−1, and the capacity retentions are nearly 100% at 2000 mA g−1 for over 500 cycles. This study not only provides a promising avenue toward manufacturing and developing new‐generation electrode materials in lithium‐ion storage but also proposes a mechanism toward comparing their performances at the molecular level.

Self-Assembly of Giant Mo240 Hollow Opening Dodecahedra

“…Hollow opening polyhedral cages have attracted considerable attention because of their aesthetic architectures and interesting application in catalysis, guest encapsulation, adsorption/separation, and ion/proton transportation. − Of the available polyhedral prototypes, Platonic bodies whose faces consist of only one single, regular polygon are particularly attractive geometric entities . Various hollow opening polyhedral cages with the shapes of small Platonic polyhedra such as tetrahedrons, cubes, and octahedrons have been constructed via different assembly strategies such as edge- and face-directed self-assembly. − Their well-defined single-crystal structures in turn guide the design and synthesis of diverse cage-based materials with desired architectures and properties. − In contrast, hollow opening cages with pentagonal dodecahedron architecture (the largest Platonic polyhedron with I h symmetry) are rarely observed, − although an edge-directed assembly approach for the synthesis of such polyhedral cages was developed by Stang et al in 1999 .…”

“…Polyoxometalates (POMs) that assemble from early transition metal oxides with rich physicochemical properties are well-known, alluring SBBs for constructing various all-inorganic/inorganic–organic hybrid hollow opening cages or polyhedral cages. − For example, several famous giant hollow opening cages (including polyhedral cages, Scheme ), such as “hedgehog-like” Mo 368 , wheel-shaped Mo 248 , truncated icosahedral Mo 132 , truncated icosahedral U 60 , and box-shaped Mo 84 , have been achieved using different POM SBBs. These giant hollow opening POM cages not only provide intriguing structures but also combine the benefits of POM clusters (e.g., their anionic nature and redox activities) and molecular cages (e.g., well-defined windows and cavities) and thus are highly promising for applications in selective catalysis, ion transport, and proton conductivity. ,− Nevertheless, it still remains a great synthetic challenge to explore new architectures to enrich the topological structures of this giant POM-cage family. In particular, the hollow opening giant polyhedral cages with high symmetry and high nuclearity are still rarely reported.…”

Boosting Cell Performance of LiNi0.8Co0.15Al0.05O2 via Surface Structure Design

“…Presently, electric vehicle technology advances require high energy density from Li‐ion batteries for commercial realization. Ni‐rich materials have attracted much attention as potential candidates due to their high reversible capacity, discharge working voltage, and relatively low costs .…”

Polyoxometalates: Tailoring metal oxides in molecular dimension toward energy applications

“…The Keggin‐type polyoxometalate Li 3 PMo 12 O 40 is evaluated in non‐aqueous conditions for Li storage . Crystals of polyoxomolybdates based on PMo 12 , Mo 72 V 30 , and Mo 132 are obtained to model the hollow balls in lithium‐ion batteries . Two‐dimensional CoMo 8 O 26 is employed in the lithium‐ion battery anode, exhibiting good charge capacity and reversibility .…”

“…277 Crystals of polyoxomolybdates based on PMo 12 , Mo 72 V 30 , and Mo 132 are obtained to model the hollow balls in lithium-ion batteries. 278 Two-dimensional CoMo 8 O 26 is employed in the lithium-ion battery anode, exhibiting good charge capacity and reversibility. 279 In addition, two-dimensional network based on [Mn 3 Mo 12 O 24 (OH) 6 (HPO 3 ) 8 (H 2 O) 6 ] 4− polyoxometalate is employed in lithium-ion battery.…”