Hard carbon (HC) is an attractive anode material for low-cost and high-energy density sodium-ion batteries (SIBs); however, its low initial Coulombic efficiency (ICE) limits its practical battery application. To overcome this problem, we reported a facile strategy to compensate the irreversible capacity loss of HC anodes simply by a chemical presodiation reaction of the HC electrode with a sodiation reagent (sodium biphenyl, Na-Bp). Benefiting from the strong sodiation ability of Na-Bp, HC anodes can be presodiated rapidly in a very short time and the presodiated HC (Na x HC) is found to have a desirable ICE of 100%. When coupled with the Na3V2(PO4)3 cathode to build a SIB full cell, the Na x HC||Na3V2(PO4)3 cell exhibits a high ICE of ∼95.0% and an elevated energy density of 218 W h kg–1, which are far superior to those of the control cell using a pristine HC anode (50% ICE and 120 W h kg–1, respectively), suggesting great advantages brought about by the chemical presodiation process. More importantly, this presodiation reaction is very mild and highly efficient and can be widely extended to a variety of Na-storage materials, offering a new route to develop high-performance Na-storage materials for practical battery applications.

Damped dispersion can be a significant component of the interaction energy in many physical and chemical processes, for example, physisorption and noncovalent complexation. For physically interpreting and modeling such processes, it is convenient to have an analytic method to calculate damped dispersion that is readily applicable across the entire periodic table. Of the available methods to calculate damped dispersion energy for interacting systems with overlapping charge distributions, we select symmetry-adapted perturbation theory (SAPT) as providing a reasonable definition, and of the possible analytic forms, we choose the D3(BJ) method. However, the available parametrizations of D3(BJ) include not only damped dispersion energy but also corrections for errors in specific exchange-correlation functionals. Here we present a parametrization that provides a physical measure of damped dispersion without such density functional corrections. The method generalizes an earlier method of Pernal and co-workers to all elements from hydrogen to plutonium.

Aqueous rechargeable Na-ion batteries (ARNBs) hold great promise for grid-scale electric energy storage because of their outstanding merits of low cost and resource abundance; however, their low energy density and poor cycling stability limit practical application. In this work, we reported a Prussian Blue (PB) analogue Na 2 Zn 3 [Fe-(CN) 6 ] 2 as a high-voltage aqueous cathode for ARNBs and achieved its stable cycling at a high operation potential of 1.13 V (vs SHE) by using of a highly concentrated NaClO 4 electrolyte. Raman spectroscopy, in situ XRD, and DFT calculations have been utilized to study the underlying mechanism of electrode performance as a function of electrolyte concentration. It was revealed that in the concentrated 17 m NaClO 4 electrolyte almost all the water molecules are coordinated with Na + ions, and the solvation energy of PB materials increases considerably with increasing salt concentrations, which broadens the electrochemical stability window of the electrolyte and greatly alleviates the dissolution of the materials. An aqueous rechargeable Na-ion battery was constructed by using a Na 2 Zn 3 [Fe(CN) 6 ] 2 cathode, a NaTi 2 (PO 4 ) 3 anode, and 17 m NaClO 4 electrolyte. This full cell demonstrates a high-voltage output of 1.6 V and an energy density of 55 Wh kg −1 (based on the total mass of the electrode-active materials), offering a viable alternative to commercial aqueous batteries for large-scale EES applications.