various sodium storage chemistry. For example, metal alloys, [6][7][8] oxides/chalcogenides, [9][10][11] phosphorus, [12][13][14] and carbonaceous materials [15][16][17] have been extensively studied as potential anodes for SIBs. Among all these anode materials, graphite exhibits a unique sodium storage electrochemistry when coupled with different electrolytes, which is of great interest. In detail, a negligible amount of sodium ions can be intercalated into the graphite structure when coupled with ester-based electrolytes because of weak binding between Na + and the graphite interlayer. [18][19][20] While sodium can be reversibly stored in graphite in ether-based electrolytes. [21,22] The answer to the riddle is that Na + and ether molecules can cointercalate between the graphene layers in graphite. [23][24][25][26] The unique sodium storage mechanism confers graphite electrodes with remarkable reversibility and fast sodium intercalation kinetics, opening a new avenue toward exploiting graphite as a promising anode for advanced SIBs. [27][28][29] However, there is still a lack of investigation at the atomic scale, such as the solvated Na + structure and possible changes during charging/discharging.Motivated by these findings, the related electrochemical performance and sodium storage mechanism have been extensively investigated, including the structural changes and sodium storage mechanisms of graphite in the sodium storage Graphite has been widely accepted for its reversible solvated sodium cointercalation mechanism into the graphite layers in ether-based electrolytes. However, the cointercalation suffers from insufficient Coulombic efficiency with high redox potentials, which significantly limits its energy output. Herein, instead of the conventional solvated Na + cointercalation into the graphite, a new coadsorptive mechanism is proposed through the microcrystalline graphite fiber (MCGF), which can reversibly store the solvated Na + at the ribboned grain boundaries and in the mesopores of the MCGF. The mechanism is manifested by various advanced spectroscopy techniques, including in situ synchrotron small-angle X-ray scattering to track the long-periodic structure evolution and ex situ synchrotron X-ray absorption fine structure to verify the interaction of solvated Na and graphite layers. The origin of the boosted rate-capability and reversibility is further revealed by density functional theory simulations and aberration-corrected transmission electron microscopy. As a proof-of-concept, the MCGF electrode exhibits high initial coulombic efficiency (92.5%), fast-charging (within 4 min), and enhanced cycling stability (≈98% retention after 800 cycles). The results provide a new understanding of the sodium storage mechanism in graphite-based materials, which may inspire further exploration of carbon electrodes for Na-ion batteries.
Polymeric dielectric materials have recently attracted much attention due to their very high potential for use as advanced energy storage capacitors. However, it is still challenging to improve the inherent...
High power consumption of nonvolatile memory is a major
challenge,
as it reduces the memory efficiency of information storage devices.
The magnetoelectric (ME) coupling in multiferroic nanocomposites,
which can be utilized in magnetoelectric random access memory, is
an effective approach to reduce power consumption in information storage.
Here, a type of ME nanocomposite embedded with 0.5 wt % Fe3O4 is presented, exhibiting higher ME voltage coefficients
for piezoelectric thin films. Specifically, the ME voltage coefficient
of the P(VDF-TrFE)/Fe3O4 composite developed
in this study is 8.97 mV/(cm·Oe), which is 17.5% higher compared
to that of the pure P(VDF-TrFE) at a H
dc of 1000 Oe. Meanwhile, the enhanced ME effect of smart nanocomposites
is characterized by the increase of diffraction peak intensity at
a microscopic level. The nanocomposite films exhibit high ME voltage
coefficients and information storage performance, providing a great
potential for creating next-generation memory devices in the realm
of artificial intelligence and wearable devices.
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