Porous Fe₂O₃ Nanoframeworks Encapsulated within Three-Dimensional Graphene as High-Performance Flexible Anode for Lithium-Ion Battery

Abstract

Integrating nanoscale porous metal oxides into three-dimensional graphene (3DG) with encapsulated structure is a promising route but remains challenging to develop high-performance electrodes for lithium-ion battery. Herein, we design 3DG/metal organic framework composite by an excessive metal-ion-induced combination and spatially confined Ostwald ripening strategy, which can be transformed into 3DG/FeO aerogel with porous FeO nanoframeworks well encapsulated within graphene. The hierarchical structure offers highly interpenetrated porous conductive network and intimate contact between graphene and porous FeO as well as abundant stress buffer nanospace for effective charge transport and robust structural stability during electrochemical processes. The obtained free-standing 3DG/FeO aerogel was directly used as highly flexible anode upon mechanical pressing for lithium-ion battery and showed an ultrahigh capacity of 1129 mAh/g at 0.2 A/g after 130 cycles and outstanding cycling stability with a capacity retention of 98% after 1200 cycles at 5 A/g, which is the best results that have been reported so far. This study offers a promising route to greatly enhance the electrochemical properties of metal oxides and provides suggestive insights for developing high-performance electrode materials for electrochemical energy storage.

Etching‐Assisted Crumpled Graphene Wrapped Spiky Iron Oxide Particles for High‐Performance Li‐Ion Hybrid Supercapacitor

“…During the early stages of long‐term cycles, the CG@SF capacity gradually decreased until the 50th cycle (as shown in Figure d), increasing continuously up to 1445 mAh g −1 during the 270th cycle, which is higher than the initial capacity (1375 mAh g −1 ). The phenomenon of increasing capacity with cycles has been reported for several nanostructured metal oxide electrodes and is commonly observed for iron oxide particles with graphene or CNT . Furthermore, the plateau region in the discharge curve (0.8 V; Figure b) decreased gradually as the cycles progressed.…”

Hierarchy Design in Metal Oxides as Anodes for Advanced Lithium‐Ion Batteries

“…Such conversion reactions can be represented as MO x + 2 x Li + + 2 x e − ↔ M + x Li 2 O, where MO x is typically transition metal oxides such as MnO x , FeO x , CoO x , and NiO x . These metal oxides are of great interest as potential high performance anode materials because of their ultrahigh theoretical specific capacity, low operating voltage, reduced toxicity, and low cost . Although Li 2 O is electrochemically inert, its nanostructured form can promote the decomposition and enhance the kinetics of the conversion reaction.…”

Niobium‐Based Oxides Toward Advanced Electrochemical Energy Storage: Recent Advances and Challenges

“…2) Conversion‐type. Based on the conversion reactions with lithium, plenty of metallic oxides can work as the conversion‐type anode materials for LIBs, such as Fe 2 O 3 , Co 3 O 4 , MnO, CuO, and so on. Although the conversion‐type electrode materials based on phase decomposition show a high capacity, the cycling stability is dissatisfied due to the considerable volume change.…”