A dual-function liquid electrolyte additive for high-energy non-aqueous lithium metal batteries

Abstract

Engineering the formulation of non-aqueous liquid electrolytes is a viable strategy to produce high-energy lithium metal batteries. However, when the lithium metal anode is combined with a Ni-rich layered cathode, the (electro)chemical stability of both electrodes could be compromised. To circumvent this issue, we report a combination of aluminum ethoxide (0.4 wt.%) and fluoroethylene carbonate (5 vol.%) as additives in a conventional LiPF6-containing carbonate-based electrolyte solution. This electrolyte formulation enables the formation of mechanically robust and ionically conductive interphases on both electrodes’ surfaces. In particular, the alumina formed at the interphases prevents the formation of dendritic structures on the lithium metal anode and mitigate the stress-induced cracking and phase transformation in the Ni-rich layered cathode. By coupling a thin (i.e., about 40 μm) lithium metal anode with a high-loading (i.e., 21.5 mg cm−2) LiNi0.8Co0.1Mn0.1O2-based cathode in coin cell configuration and lean electrolyte conditions, the engineered electrolyte allows a specific discharge capacity retention of 80.3% after 130 cycles at 60 mA g−1 and 30 °C which results in calculated specific cell energy of about 350 Wh kg−1.

A solvent molecule reconstruction strategy enabling a high-voltage ether-based electrolyte

“…The content and ratio of inorganic fluorides (located around 645.0 eV) of LMA cycled in the Hybrid-DOL/PDOL-TTE are higher than in the other two electrolytes. 39–41 Additionally, the results from the C 1s XPS spectra show that the LMA cycled in the Hybrid-DOL/PDOL-TTE has the highest signal intensity of the C–O bond and the weakest signal intensity of the C–C bond, 42 suggesting abundant polyether-derived segments and a low ratio of unwanted organic species are formed in the SEI layer. The robust SEI layer containing rich LiF and polyether-derived segments enabled by the Hybrid-DOL/PDOL-TTE can effectively suppress the Li dendrite growth and facilitate uniform Li stripping/plating.…”

Trace weak solvation environment enabling ultra-stable high-voltage solid-state lithium metal battery

“…The PDTL electrolyte also exerts paramount effect to suppress the irreversible phase transformation of NCM811 particles from layered structure to rock-salt phase, as suggested by the higher peak ratio of I(003)/I(104) from the X-ray diffraction (XRD) results 48 (Supplementary Fig. 44).…”

Ultralight Porous Cu Nanowire Aerogels as Stable Hosts for High Li-Content Metal Anodes

“…Considerable efforts have been made to address the problem of Li dendrite growth and unstable SEI. Based on the battery configuration and reaction mechanism, the strategies could be summarized as anode interface engineering (artificial SEI and interface reconstruction), − separator modification engineering, − electrolyte modification engineering, − and anode structure engineering. − Among them, the anode structure engineering, including reconstruction of Li metal and employment of porous current collectors, shows excellent effects in Li dendrite suppression. − Conventional used porous current collectors, including porous carbon nanomaterials and porous metal materials, have been widely investigated to stabilize Li metal anodes. − Compared with carbon-based current collectors, porous metal current collectors with appropriate specific surface areas are more beneficial for uniform distribution of charge density and ion concentration as well as the promotion of sufficient inner space to accommodate the deposition of Li metal and thereby could more effectively suppress the metal dendrite formation. , The introduction of porous metal current collectors has proven to be effective to inhibit Li dendrites and accommodate homogeneous Li deposition, thus pushing the commercial proceedings of highly stabilized Li metal batteries. − However, most reported porous metal hosts usually have small pore volumes and account for more than 83 wt % of the composite anode . The high density of the metal current collector will inevitably increase the portion of the inactive part in the electrode, thereby lowering the energy density of the battery. − Hence, reducing the mass of metal current collectors is significantly important for elevating the energy density of batteries.…”