Multifunctional High-Efficiency Additive with Synergistic Anion and Cation Coordination for High-Performance LiNi_0.8Co_0.1Mn_0.1O₂ Lithium Metal Batteries

Abstract

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.

Interfacial Film Regulation and Electrochemical Performance Using Cyclopropane Sulphonic Amide Functionalized Electrolyte to Stabilize Lithium Metal Batteries with a LiNi0.8Mn0.1Co0.1O2 Cathode

“…In evidence, in the cell cycled in the blank electrolyte, Li deposited on the Cu electrode grew as needle-like Li and Li dendrites presented to the surface of the electrode; meanwhile, the Li on the Cu foil was deposited very unevenly, and pits appeared on the electrode surface (Figure a,b). As is known to all, the existence of Li dendrites will increase the contact area within the electrolyte and Li anode, resulting in consistent side reactions, and eventually, more dead Li will be deposited on the Cu foil . With 1 wt % CPSA added, the Li deposited on the Cu foil in the form of a bulk structure with few dendrites (Figure c,d).…”

“…As is known to all, the existence of Li dendrites will increase the contact area within the electrolyte and Li anode, resulting in consistent side reactions, and eventually, more dead Li will be deposited on the Cu foil. 33 With 1 wt % CPSA added, the Li deposited on the Cu foil in the form of a bulk structure with few dendrites (Figure 5c,d). Thus, the excessive electrolyte consumption was reduced and the efficiency of the Li stripping/ plating process was improved.…”

Constructing Low‐Solvation Electrolytes for Next‐Generation Lithium‐Ion Batteries

“…Liao et al. at the Chinese University of Science and Technology creatively used RbNO 3 as an electrolyte additive [29] . Specifically, the low concentration of rubidium ions (Rb + ) has a lower reduction potential than that of Li + and participate in forming the weak solvation sheath of Li + , which generates a highly conductive SEI layer containing LiN x O y and Li 3 N. The additive can regulate the deposited morphology of Li + and further avoid the formation of Li dendrites.…”

Roles of Trimethyl Borate in Constructing an Interphase on Li Anode: Angel or Demon?

“…NCM811 has an unparalleled advantage of high specific capacity and has taken up half of the positive electrode material market share . Nevertheless, it confronts severe challenges at a high cut-off voltage, including transition-metal dissolution and particle cracking owing to its structural instability .…”