Aqueous zinc-ion batteries (ZIBs) have attracted great research interest for use in large-scale energy storage devices due to their inherent safety, environmental friendliness, and low cost. Unfortunately, dendrite growth and interfacial side reactions during the plating/stripping process triggered by uneven electric field distribution on the surface of the Zn anode seriously hinder the further development of aqueous ZIBs. Here, practical and inexpensive sodium tartrate (STA) is used as an electrolyte additive to construct a stable electrode–electrolyte interface, in which STA adsorbs preferentially on the Zn metal surface, contributing to promoting homogeneous Zn deposition. Moreover, STA interacts more strongly with Zn2+, which takes the place of the water molecules in the solvated shell and prevents the development of side reactions. In symmetrical cells and full cells, flat Zn anodes can therefore demonstrate remarkable cycle stability, opening the door for the development of cost-effective and effective electrolyte engineering techniques.
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Aqueous zinc-ion batteries (ZIBs) are attaining increasing attention for their high safety and low cost. Despite significant progresses in realizing high-performance cathode material for ZIBs, simultaneously endowing them with high capacity and fast-charging capability, the long-term cycling stability remains a major unsolved challenge. In this work, a polyoxovanadate cluster of (NH4)8[V19O41(OH)9]·11H2O (NOV) is defined as a cathode material for ZIBs that contains mixed-valence vanadium sites (V4+ and V5+). A maximum of 26 electrons can be accommodated in one [V19O41(OH)9]8− {V19O50} cluster, contributing to the high theoretical specific capacity of 328 mA·h·g−1. The Ti3C2Tx MXene nanosheets are incorporated into NOV with the help of ionic liquid (IL) linkers to restrain the dissolution of vanadium species and facilitate electron transport across the electrode. The interfacial bonding, anion exchange, and electrostatic interactions among NOV and MXene are provided by IL liquid. The nanohybrid of NOV-IL-MXene endows excellent contact between MXene and NOV, thereby enhanced charge transfer is observed at interface. Subsequently, the as-synthesized NOV-IL-MXene cathodes exhibit high discharge capacity of 413 mA·h·g−1 at 0.2 A·g−1 even at high mass loading of 5.2 mg·cm−2, remarkable rate performance of 182 mA·h·g−1 at 10 A·g−1, and impressive cycling stability of 94% capacity retention after 2000 cycles. This work opens up new opportunities to develop advanced polyoxovanadate hybrid cathodes for low-cost and high-performance aqueous ZIBs.
Silicon (Si) has been investigated as a promising anode material because of its high theoretical capacity (4200 mAh g-1). However, silicon anode suffers from huge volume changes during repeated charge–discharge cycles. In this work, inspired by a remarkable success of the glutinous rice mortar in the Great Wall with ca. 2000-year history, amylopectin (AP), the key ingredient responsible for the strong bonding force, is extracted from glutinous rice and utilized as a flexible, aqueous, and resilient binder to address the most challenging drastic volume-expansion and pulverization issues of silicon anode. Additionally, the removal of toxic N-methyl-2-pyrrolidone (NMP) organic solvent makes the electrode fabrication process environmentally friendly and healthy. The as-prepared Si-AP electrode with 60 wt% of Si can uphold a high discharge capacity of 1517.9 mAh g−1 at a rate of 0.1 C after 100 cycles. The cycling stability of the Si-AP has been remarkably improved in comparison with both traditional polyvinylidene fluoride (PVDF) and aqueous carboxymethylcellulose (CMC) binders. Moreover, when the content of silicon in the Si-AP electrode increases to 70 wt%, a high discharge capacity of 1463.1 mAh g−1 can still be obtained after 50 cycles at 0.1° C. These preliminary results suggest that the sustainably available and environmentally benign amylopectin binders could be a promising choice for the construction of highly stable silicon anodes.
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