Search

Due to the Earth’s scarcity of lithium, replacing lithium with earth-abundant and low-cost sodium for sodium-ion batteries (SIBs) has recently become a promising substitute for lithium-ion batteries. However, the shortage of appropriate anode materials limits the development of SIBs. Here, a dual-carbon conductive network enhanced GeP5(GeP5/acetylene black/partially reduced graphene oxide sheets (GeP5/AB/p-rGO)) composite is successfully prepared by a facile ball milling method. The dual-carbon network not only provides more transport pathways for electrons but also relaxes the huge volume change of the electrode material during the charge/discharge process. Compared with only AB- or GO-modified GeP5(GeP5/AB or GeP5/GO) composite, the GeP5/AB/p-rGO composite shows a superior sodium storage performance with an excellent rate and cycle performance. It delivers a high reversible capacity of 597.5 and 175 mAh/g at the current density of 0.1 and 5.0 A/g, respectively. Furthermore, at the current density of 0.5 A/g, the GeP5/AB/p-rGO composite shows the reversible capacity of 400 mAh/g after 50 cycles with a little capacity attenuation. All above results prove that the GeP5/AB/p-rGO composite has a good prospect of application as an anode material for SIBs.

In this work, a flexible and self-supporting P-doped carbon cloth (FPCC), which is composed of interwoven mesh of hollow microtubules with porous carbon walls, is prepared via a vacuum-sealed doping technology by employing the commercially available cotton cloth as sustainable and scalable raw material. When directly used as binder-free anode for sodium-ion batteries, the as-prepared FPCC delivers superior Na-storage properties in terms of specific capacity up to 242.4 mA h g–1, high initial Coulombic efficiency of ∼72%, excellent rate capabilities (e.g., 123.1 mA h g–1at a high current of 1 A g–1), and long-term cycle life (e.g., ∼88% capacity retention after even 600 cycles). All these electrochemical data are better than the undoped carbon cloth control, demonstrating the significance of P-doping to enhance the Na-storage properties of cotton-derived carbon anode. Furthermore, the technologies of electrochemical impedance spectroscopy and galvanostatic intermittent titration technique are implemented to disclose the decrease of charge transfer resistance and improvement of Na-migration kinetics, respectively.

Recent experiments show that membrane ATPases are capable of absorbing free energy from an applied oscillating electric field and converting it to chemical bond energy of ATP or chemical potential energy of concentration gradients. Presumably these enzymes would also respond to endogenous transmembrane electric fields of similar intensity and waveform. A mechanism is proposed in which energy coupling is achieved via Coulombic interaction of an electric field and the conformational equilibria of an ATPase. Analysis indicates that only an oscillating or fluctuating electric field can be used by an enzyme to drive a chemical reaction away from equilibrium.In vivo, the stationary transmembrane potential of a cell must be modulated to become “locally” oscillatory if it is to derive energy and signal transduction processes.

Recent experiments show that membrane ATPases are capable of absorbing free energy from an applied oscillating electric field and converting it to chemical bond energy of ATP or chemical potential energy of concentration gradients. Presumably these enzymes would also respond to endogenous transmembrane electric fields of similar intensity and waveform. A mechanism is proposed in which energy coupling is achieved via Coulombic interaction of an electric field and the conformational equilibria of an ATPase. Analysis indicates that only an oscillating or fluctuating electric field can be used by an enzyme to drive a chemical reaction away from equilibrium. In vivo, the stationary transmembrane potential of a cell must be modulated to become “locally” oscillatory if it is to derive energy and signal transduction processes.