Reconstructed Orthorhombic V2O5 Polyhedra for Fast Ion Diffusion in K-Ion Batteries

• Published in: Chem Vol. 5; no. 1; pp. 168 - 179
• Main Authors: Zhu, Yun-Hai, Zhang, Qi, Yang, Xu, Zhao, En-Yue, Sun, Tao, Zhang, Xin-Bo, Wang, Sai, Yu, Xi-Qian, Yan, Jun-Min, Jiang, Qing
• Format: Journal Article
• Language: English
• Published: Elsevier Inc 10.01.2019
• Subjects: DFT calculation; high power density; potassium-ion full battery; reconstruction; SDG7: Affordable and clean energy; vanadium pentoxide; DFT calculation; reconstruction; SDG7: Affordable and clean energy; high power density; vanadium pentoxide; potassium-ion full battery
• ISSN: 2451-9294; 2451-9294
• DOI: 10.1016/j.chempr.2018.10.004

Potassium-ion batteries (KIBs) are a promising alternative to lithium-ion batteries because of the abundance, low cost, and redox potential of K; however, the significantly larger radius of K+ inevitably destabilizes the crystal structure of the cathode material, impeding the diffusion of K+. Here, to lower the insertion energetics and diffusion barriers of K+, we synthesizedδ-K0.51V2O5 nanobelts (KVOs) with a large interlayered structure and optimized growth orientation by reconstructing the V–O polyhedra of orthorhombic V2O5; these exhibited a high average voltage (3.2 V), high capacity (131 mAh g−1), and superior rate capability even at 10 A g−1. By coupling the electrochemical experiments with theoretical calculations, we found that the excellent K-ion storage performance of KVO is attributed to its large interlayered structure and unique 1D morphology. Additionally, we assembled a full KIB composed of KVO and graphite with high energy and power densities, proving its feasibility as a promising new battery. [Display omitted] •Bilayered δ-K0.51V2O5 nanobelts were developed via reconstruction of α-V2O5•A new phase was reversibly generated upon K insertion and extraction•Large interlayer space and optimized growth orientation enabled fast K+ diffusion As a result of increased energy demand and the prices of fossil fuels, rational use of renewable energy sources has become a growing global concern. Rechargeable potassium-ion batteries (KIBs) are emerging as a promising large-scale energy storage system for storing renewable energy because of the abundance and low cost of potassium resources. However, the significantly larger radius of K+ destabilizes the crystal structure of host materials, impeding the successful application of KIBs. Here, to unlock the compact structure of α-V2O5 for the diffusion of K+, we developed single-crystalline bilayered δ-K0.51V2O5 nanobelts (KVOs) via reconstruction of α-V2O5 and achieved excellent K-storage performance. Importantly, the high-energy- and high-power-density KIB constructed with KVO and graphite proves its feasibility in large-scale energy storage systems. To unlock the compact structure of α-V2O5 for the diffusion of K+, we developed single-crystalline bilayered δ-K0.51V2O5 nanobelts via reconstruction of α-V2O5. Benefiting from the large interlayer space and optimized growth orientation, δ-K0.51V2O5 exhibits suitable accommodation sites and fast diffusion paths for K+, enabling high capacity and rate capability. Additionally, the achievement of a high-energy- and high-power-density full K-ion battery proves its feasibility in large-scale energy storage systems.