The Jahn-Teller Effect for Amorphization of Molybdenum Trioxide towards High-Performance Fiber Supercapacitor

Abstract

Amorphous pseudocapacitive nanomaterials are highly desired in energy storage applications for their disordered crystal structures, fast electrochemical dynamics, and outstanding cyclic stability, yet hardly achievable using the state-of-the-art synthetic strategies. Herein, for the first time, high capacitive fiber electrodes embedded with nanosized amorphous molybdenum trioxide (A-MoO3-x) featuring an average particle diameter of ~20 nm and rich oxygen vacancies are obtained via a top-down method using α-MoO3 bulk belts as the precursors. The Jahn-Teller distortion in MoO6 octahedra due to the doubly degenerate ground state of Mo5+, which can be continuously strengthened by oxygen vacancies, triggers the phase transformation of α-MoO3 bulk belts (up to 30 μm long and 500 nm wide). The optimized fibrous electrode exhibits among the highest volumetric performance with a specific capacitance (CV) of 921.5 F cm-3 under 0.3 A cm-3, endowing the fiber-based weaveable supercapacitor superior CV and EV (energy density) of 107.0 F cm-3 and 9.5 mWh cm-3, respectively, together with excellent cyclic stability, mechanical robustness, and rate capability. This work demonstrates a promising strategy for synthesizing nanosized amorphous materials in a scalable, cost-effective, and controllable manner.

Facile Synthesis of Hybrid Anodes with Enhanced Lithium-Storage Performance Realized by a “Synergistic Effect”

“…60 The amorphous phases with isotropy property can relieve the volume expansion during lithiation/delithiation processes and improve the cycling stability of the electrodes. 61 The SEM images of cycled electrodes further reveal the superior mechanical stability of SnO 2 /Si@G. As displayed in Figure 6a−c, SnO 2 /Si@G electrodes after 100 cycles show an intact surface with SEM, in contrast to the severely cracked surface for nano-SnO 2 and nano-Si electrodes. More importantly, the thickness of nano-SnO 2 electrodes increases from 11.0 to 13.1 μm after 100 cycles, with an expansion ratio of 19.1%.…”

“…Combining with the CV, XRD, and XPS data of cycled SnO 2 /Si@G electrodes (Figures b, S22, and S23), it can be deduced that the tin oxides regenerated after charging are amorphous . The amorphous phases with isotropy property can relieve the volume expansion during lithiation/delithiation processes and improve the cycling stability of the electrodes …”

A multifunctional paper-based supercapacitor with excellent temperature adaptability, plasticity, tensile strength, self-healing, and high thermoelectric effects

“…4c and d) displays comparison maps of volumetric specic capacitance and energy density of APC-PVA@ZnCl 2 with reported works. [34][35][36][37][38][39][40][41][42] It is obvious that our work can be compared with those excellent works in recent years. All in all, these results demonstrate that the APC-PVA@ZnCl 2 supercapacitor has excellent environmental adaptability, showing its potential application value in different environments.…”

Mechanisms for self‐templating design of micro/nanostructures toward efficient energy storage

“…As one of the most widely used EES devices, SCs possess intriguing features of excellent charge/discharge characteristics and a long servicing lifespan. [125][126][127][128] Especially, the hybrid supercapacitors combine the merits of batteries (high energy density) and SCs (high power capability) simultaneously. [129][130][131] However, the battery-type electrodes of the hybrid supercapacitors normally exhibit sluggish kinetics and unsatisfactory cycle life owing to the long diffusion pathway and the large volume change.…”