Xiaomeng Liu,Mengying Chen,Guoyuan Xiong,Yafei Guo,Lingzong Meng,Tianlong Deng
The phase equilibria of the ternary system at 298.15 and 338.15 K were investigated by the isothermal dissolution equilibrium and wet-reside solid phase (Schreinemarkers rule) methods. The solubilities and the physicochemical properties containing density and refractive index were obtained experimentally. Then, the phase diagrams and the diagrams of physicochemical properties against the composition in the ternary system at two temperatures were proposed. The phase diagrams of this system at two temperatures contain two invariant points, three solubility curves, and three crystallized regions corresponding to NaNO 3 , RbNO 3 and double salt NaRb 2 (NO 3 ) 3 . According to the phase diagrams at 298.15 and 338.15 K, a novel separation process of RbNO 3 from the mixture solution of NaNO 3 was established for the first time, and the separation rate of RbNO 3 in the mixed solution reached 43.75% in a single yield. This work provides an efficient and reliable RbNO 3 green recovery method from the eluent solution of NaNO 3 efficiently.
Can Liao,Longfei Han,Xiaowei Mu,Yulu Zhu,Na Wu,Jingyi Lu,Yonghui Zhao,Xingjun Li,Yuan Hu,Yongchun Kan,Lei Song
Safety and high energy density have long restricted the large-scale practical application of lithium metal batteries because of the unbridled growth of lithium dendrites and the rapid deteriorating cycle performance of the LiNi0.8Co0.1Mn0.1O2 (NCM811) cathode. Herein, an additive of RbNO3 with multiple functions is proposed for dendrite-free NCM811 lithium metal batteries. Benefiting from the electrostatic shielding effect formed by Rb+ during the Li+ deposition process and the solvation effect of NO3– to regulate lithium deposition, a high Coulombic efficiency of 95.02% (compared with the low Coulombic efficiency of 89.37% in the blank electrolyte) is acquired in Li//Cu cells, and the uniform growth of the lithium metal deposition with a large strawberry-like morphology is achieved. Moreover, when a cathode of NCM811 matches with a lithium metal anode, an extraordinary capacity retention of 93.67% after 200 cycles with a high Coulombic efficiency of 99.7% in the electrolyte with the RbNO3 system (a capacity retention of 80.1% with a Coulombic efficiency of 98.0% for the blank electrolyte) is achieved at 1C. This work provides guidance for the development of high-efficiency additives with dual synergistic regulation effects of anions and cations for lithium metal batteries in the future.