Scalable Room-Temperature Synthesis of Multi-shelled Na3(VOPO4)2F Microsphere Cathodes

Abstract

To save energy and decrease cost, it is essential to explore a low-temperature green process for the synthesis of electrode materials. We developed a facile onestep room-temperature strategy for the scalable fabrication of Na 3 (VOPO 4 ) 2 F (e.g., 150 g per patch). UV-vis spectra are first employed to investigate the chargetransfer feature during charge and discharge process. The as-synthesized product delivers superior rate capability and outstanding cycling stability: 81 mA hr g À1 and about 70% capacity retention after 3,000 cycles at 15-C rate.

Toward High Power‐High Energy Sodium Cathodes: A Case Study of Bicontinuous Ordered Network of 3D Porous Na3(VO)2(PO4)2F/rGO with Pseudocapacitance Effect

“…The process of preparing bicontinuous ordered 3D porous NVOPF/rGO nanocomposite by a two‐step strategy (solvothermal plus ESD method) is shown in Figure . To synthesize fluorophosphates such as NVPF‐NVOPF is more difficult than that of NVP, since the element F is easy to lose and leads to NVP impurity, especially for the electric field related method such as ESD or electrospinning method . The advantages of proposed two‐step strategy are largely expand application scope of ESD from oxides, sulfides, and selenides to other types of materials, i.e., fluorides in this work.…”

“…We proposed a two‐step strategy that is ESD combined with solvothermal method to construct a bicontinuous network of 3D porous NVOPF/rGO with relatively ordered structure, which is directly deposited on the current collector without any additional conductive additives and binders. This method can avoid the loss of F element during synthesis, leading to phase pure NVOPF without other impurities. It only needs 3.5% rGO in the final composite to construct such bicontinuous architecture.…”

Vanadium‐Based Nanomaterials: A Promising Family for Emerging Metal‐Ion Batteries

“…Besides, the superior low temperature performance was also demonstrated with a capacity retention of 76.4% as the temperature decreased from 25 to −25 °C. Notably, Hu group reported a rapid room‐temperature strategy for large‐scale synthesis (150 g per batch) of NVOPF microspheres very recently, which is very significant for speeding up the commercialization of NVOPF cathode for SIBs.…”

Recent Progress of Layered Transition Metal Oxide Cathodes for Sodium‐Ion Batteries

“…Therefore, the main concern in the SIB system is to find suitable electrode materials, especially cathode materials, which, to a great extent, determine the energy density of a battery. Several different groups of cathode materials for SIBs have been investigated, including polyanionic compounds, metal hexacyanometalates, metal oxides, and organic compounds . Among the candidates, transition metal oxide cathodes (M = Fe, Mn, Ni, Co, Cr, Ti, V, and their combinations) are particularly promising and have been extensively exploited due to their simple structure, ease of synthesis, high operating potential, and feasibility for commercial production.…”