Aligned Ferric Oxide/Graphene with Strong Coupling Effect for High-Performance Anode

Abstract

Herein, the strong coupling effect on the atomic scale and the aligned structure on microscale are introduced simultaneously to establish a superior ferric oxide/graphene anode. The strong coupling between graphene and ferric oxide (Fe 3 O 4 ) is established by the high-temperature and long-term in situ hydrothermal reduction. The aligned architecture is elaborately introduced by an upward magnetostatic field. The strong coupling effect enhances the adsorption for a lithium ion (Li + ) and conductivity due to the formation of an imbalanced electric field. In terms of the aligning architecture, the loosely vertical-aligned Fe 3 O 4 /reduced graphene oxide hybrid (vertical to the current collector) induced by an upward magnetostatic field minimizes the Li + diffusion tortuosity, lowers the Li + diffusion barrier, and relaxes the volume stress. Therefore, the vertical-reduced graphene oxide/Fe 3 O 4 composite electrode shows an excellent performance, such as 610 mA h g −1 at 10 A/g and about 700 mA h g −1 at 3 A/g after 1000 cycles. The in-deep enhanced mechanism is explored and confirmed by experiments and density functional theory calculations. This work provides an available design thinking for advanced anodes.

Extra Li-Ion Storage and Rapid Li-Ion Transfer of a Graphene Quantum Dot Tiling Hollow Porous SiO2 Anode

“…After the cycling test, the EIS plots are measured (Figure d) and the shape is consistent with the attested equivalent circuit model (Figure S8a). For the three electrodes, unfortunately, the solid electrolyte interphase (SEI) film resistances ( R f ) are almost equal, indicating that the introduction of rGO and GDs would not stabilize the surface of HSiO 2 . The abundant SEI film on the surface of HSiO 2 @GDs (Figure S8b) also confirms the result.…”

“…However, the introduction of graphene still presents some disadvantages. (1) Using the conventional doctor-blade method and the graphene-encapsulated strategy (such as a three-dimensional graphene scaffold) to prepare anodes, the graphene tends to be vertical with the Li + diffusion direction, causing sluggish reaction kinetics (Figure a,b) . (2) Generally, the size of graphene is in microscale and the size of active materials is in nanoscale, therefore, the interfaces (point-to-point contact) between active materials and graphene are insufficient due to the surface tension of graphene.…”

Aerogel Constructed by Ultrasmall Mn-Doped Silica Nanoparticles for Superior Lithium-Ion Storage

“…43 Commonly, the capacity is proportional to the adsorption energy for Li + . 44 As shown in Figure 5j, the adsorption energy for the Li + in the SiO 2 , Mn-SiO 2 , and Mn-SiO 2 + Ov are −1.40, −4.62, and −5.81 eV, respectively. Table S2 presents the obtained energy of models, and the calculation method for adsorption energy is expressed as eq S5.…”

“…The result indicates that the doping of Mn 2+ and Mn 3+ would catch the outer electron shells, boosting the holes in the valence band ( E v ) of silicon atoms (p-type doping) and leading to the mobility of electrons in the E v (Figure S10). Commonly, the capacity is proportional to the adsorption energy for Li + . As shown in Figure j, the adsorption energy for the Li + in the SiO 2 , Mn-SiO 2 , and Mn-SiO 2 + Ov are −1.40, −4.62, and −5.81 eV, respectively.…”

MXene Contact Engineering for Printed Electronics

“…After the plasma‐assisted mechanical chemical treatment, the layered structure of TiC 2 T x MXenes is distorted, and numerous defects act as additional active sites of lithium ions, so that the electrochemical energy storage capacity of the lithium‐ion battery is enhanced. [ 178 ] In the same way, Mo vacancies with uniform distribution are constructed in the composite material Mo x S/TiO 2 /Ti 3 C 2 , and the introduction of Mo vacancies inhibits the recombination of carrier recombination and increases plentiful active sites for photocatalytic hydrogen production. [ 179 ] Layered TiO 2 oxidized from Ti 3 C 2 T x was used as a catalyst for the synthesis of ethylene (M–TiO 2 ).…”