Stabilizing lithium metal anode by octaphenyl polyoxyethylene-lithium complexation

Abstract

Lithium metal is an ideal anode for lithium batteries due to its low electrochemical potential and high theoretical capacity. However, safety issues arising from lithium dendrite growth have significantly reduced the practical applicability of lithium metal batteries. Here, we report the addition of octaphenyl polyoxyethylene as an electrolyte additive to enable a stable complex layer on the surface of the lithium anode. This surface layer not only promotes uniform lithium deposition, but also facilitates the formation of a robust solid-electrolyte interface film comprising cross-linked polymer. As a result, lithium|lithium symmetric cells constructed using the octaphenyl polyoxyethylene additive exhibit excellent cycling stability over 400 cycles at 1 mA cm −2 , and outstanding rate performance up to 4 mA cm −2 . Full cells assembled with a LiFePO 4 cathode exhibit high rate capability and impressive cyclability, with capacity decay of only 0.023% per cycle.

Water based synthesis of highly conductive GaxLi7−3xLa3Hf2O12 garnets with comparable critical current density to analogous GaxLi7−3xLa3Zr2O12 systems

“…However, modern day LIBs use liquid-based electrolytes that enable propagation of lithium dendrites, and so pose significant safety concerns with the use of a Li metal anode 3 . Despite intensive research to prevent dendritic growth [4][5][6][7][8][9][10] , a practical solution to eliminate this issue remains elusive. Furthermore, these electrolytes are flammable, toxic, non-renewable and often have a limited electrochemical window (preventing use of high V cathode materials), hence they are not ideal for the high energy demands of modern-day society 2,[11][12][13][14] .…”

Li-containing alloys beneficial for stabilizing lithium anode: a review

“…For example, the absence of volatile or flammable compounds is expected to make solid electrolytes safer than their liquid counterparts at elevated temperatures [11]. Additives, can decompose, polymerize or adsorb on the Li surface, modifying the physico-chemical properties of the SEI and therefore regulating the current distribution during Li deposition [19,23,134]. Solvents, i.e, the ionic liquid, shows an exciting role in improving the low temperature performances of batteries [135].…”

“…Recently, our group employed octaphenyl polyoxyethylene as an electrolyte additive to enable a stable complex layer on the surface of the lithium anode. This surface layer not only promoted uniform lithium deposition, but also facilitated the formation of a robust SEI film [23]. While developed new type of modified separators are expected to physically suppress the growth of lithium dendrites.…”

Polysiloxane Cross‐Linked Mechanically Stable MXene‐Based Lithium Host for Ultrastable Lithium Metal Anodes with Ultrahigh Current Densities and Capacities

“…Tremendous efforts have been devoted to overcoming these issues, and conventional approaches include the construction of artificial SEI layers, [ 15,16 ] the use of electrolyte additives, [ 17–19 ] and separator modification. [ 20,21 ] Although great advances have been made, the fundamental issues of large electrode volume changes during Li plating–stripping cycles remain unsolved.…”