Surface Condition Changes in Lithium Metal Deposited in Nonaqueous Electrolyte Containing HF by Dissolution‐Deposition Cycles

Abstract

The dissolution-deposition cycle behavior of Li metal electrodeposited in nonaqueous electrolyte containing a small amount of HF was investigated. In the first deposition process, Li particles with a smooth hemispherical shape were deposited on Ni in 1.0 M LiCF 3 SO 3 /propylene carbonate containing HF. The morphology of these fine Li particles is due to electrodeposition via migration of Li ϩ ions through a thin and compact surface film consisting of a LiF/Li 2 O bilayer, which was produced via surface modification by HF. After the first dissolution process, a residual film was observed on the entire surface of the Ni substrate. This residual film is derived from the surface film on the Li particles. Moreover, the residual film continuously accumulated on the electrode during the cycling. On the other hand, it was found that the coulombic efficiency of Li deposition-dissolution during cycling was much improved by the addition of HF. Unfortunately, the formation of dendritic Li was observed after the 45th cycle, suggesting that the accumulated thick residual film on the Li surface inhibits the supply of HF to the Li surface during the deposition process.

The synergetic effect of lithium polysulfide and lithium nitrate to prevent lithium dendrite growth

“…Among various approaches to overcoming the issues of lithium metal anode, it is recognized that electrolyte selection is one of the most dominant factors for stabilizing the lithium metal surface [14][15][16][17][18][19][20][21][22][23][24][25][26][27] . Although various polymeric and ceramic electrolytes have been demonstrated to suppress lithium dendrite growth [14][15][16][17][18][19][20] , their ionic conductivity, interfacial impedance, mechanical moduli or chemical stability when in contact with metallic lithium were not satisfying and still need further improvement for their implementation.…”

“…Although various polymeric and ceramic electrolytes have been demonstrated to suppress lithium dendrite growth [14][15][16][17][18][19][20] , their ionic conductivity, interfacial impedance, mechanical moduli or chemical stability when in contact with metallic lithium were not satisfying and still need further improvement for their implementation. In liquid electrolytes, many additives including organic and inorganic compounds have been used to improve the stability of the SEI layer [21][22][23][24][25] . However, the low solubility of many additives in the electrolyte and their rapid consumption during cycling undermines their effectiveness in suppressing dendrite growth.…”

Electrochemistry of metals and semiconductors in fluoride media

“…This study has also been extended to the evaluation of initial films present on thin Li sheets and the role of HF on their deposition and dissolution behaviour [138,139]. These studies reveal the presence of 2-5 nm thin Li 2 O/LiF bilayer, which ensures better uniformity of Li deposition.…”

A single-ion gel polymer electrolyte system for improving cycle performance of LiMn2O4 battery at elevated temperatures

“…To give insight into the positive effect of PLTB-based electrolyte in preventing the generation of Li dendrites [28][29][30][31][32], the surface morphology of lithium metal foils was studied by SEM observation after 100 cycles, which were depicted in Fig. 6(d-f).…”