Minglun Li,Bilin Zhuang,Yuyuan Lu,Zhen-Gang Wang,Lijia An
We present a novel method for obtaining salt polarizabilities in aqueous solutions based on our recent theory for the refractive index of salt solutions, which predicts a linear relationship between the refractive index and the salt concentration at low concentrations, with a slope determined by the intrinsic values of the salt polarizability and the density of the solution. Here we apply this theory to determine the polarizabilities of 32 strong electrolyte salts in aqueous solutions from refractive index and density measurements. Setting Li+ as the standard ion, we then determine the polarizabilities of seven cations (Na+, K+, Rb+, Cs+, Ca2+, Ba2+, and Sr2+) and seven anions (F–, Cl–, Br–, I–, ClO4–, NO3–, and SO42–), which can be used as important reference data. We investigate the effect of temperature on salt polarizabilities, which decreases slightly with increasing temperature. The ion polarizability is found to be proportional to the cube of bare ionic radius (rbare3) for univalent ions, but the relationship does not hold for multivalent ions. Contrary to findings of Krishnamurti, we find no significant linear relationship between ion polarizability and the square of the atomic number (N2) for smaller ions.
Current all-solid-state lithium battery (ASSLB) manufacturing typically involves laborious fabrication and assembly of individual electrodes and solid electrolyte, which inevitably result in large interfacial resistances. Moreover, due to the unfavorable mechanical strength, most solid electrolytes are fabricated to be overly thick and are incapable of retarding lithium dendrite formation. These factors limit the attainable energy density and cyclability of ASSLBs. Here, a novel integrated cathode/solid electrolyte for scalable ASSLB manufacturing is reported by directly fabricating an ultrathin yet robust fiber network reinforced solid electrolyte on the cathode. The integrated design allows continuous ion conduction at both the interface and the entire cathode, thereby considerably reducing interfacial resistance and enabling higher cathode loading. Meanwhile, the strong fiber network endows the solid electrolyte with an ultrasmall thickness and superior dendrite suppression capability. As a result, the newly-developed Li/LiFePO 4 ASSLB achieves a high capacity of 155.2 mAh g –1 at 0.5 C and 45 °C with capacity retention of 84.3% after 500 cycles. Even with a cathode loading of 13 mg cm –2 , the battery still delivers a capacity of 124.1 mAh g –1 . Additionally, a pouch cell with this integrated design displays good electrochemical performance and safety, showing great promise for practical applications.