Hexafluoroisopropyl Trifluoromethanesulfonate‐Driven Easily Li⁺ Desolvated Electrolyte to Afford Li||NCM811 Cells with Efficient Anode/Cathode Electrolyte Interphases

Abstract

Solid electrolyte interphase (SEI) and cathode electrolyte interphase (CEI) with optimized components and structures are considered to be crucial for lithium‐ion batteries. Here, gradient lithium oxysulfide (Li2SOx, x = 0, 3, 4)/uniform lithium fluoride (LiF)‐type SEI is designed in situ by using hexafluoroisopropyl trifluoromethanesulfonate (HFPTf) as electrolyte additive. HFPTf is more likely to be reduced on the surface of Li anode in electrolytes due to its high reduction potential. Moreover, HFPTf can make Li+ desolvated easily, leading to the increase in the flux of Li+ on the surface of Li anode to avoid the growth of Li dendrites. Thus, the cycling stability of Li||Li symmetric cells is improved to be 1000 h at 0.5 mA cm−2. In addition, HFPTf‐contained electrolyte could make Li||NCM811 batteries with a capacity retention of 70% after 150 cycles at 100 mA g−1, which is attributed to the formation of uniform and stable CEI on the cathode surface for hindering the dissolvation of metal ions from the cathode. This study provides effective insights on the strong ability of additives to adjust electrolytes in “one phase and two interphases” (electrolyte and SEI/CEI).

Li2CO3/LiF‐Rich Heterostructured Solid Electrolyte Interphase with Superior Lithiophilic and Li+‐Transferred Characteristics via Adjusting Electrolyte Additives

“…In addition, the unstable SEI will also induce uneven ionic diffusion and Li deposition, which would result in uncontrolled dendrite growth and poor electrochemical performance. [9][10][11] Therefore, high-quality SEI is highly desired for superior LMBs.Recently, extensive efforts have been devoted to stabilizing Li anode by engineering a robust SEI mainly through electrolyte formulation [12][13][14][15][16] and artificial SEI. [17][18][19][20] However, the role of the structures and components of SEI has long been debated, and the transport mechanism of Li + ions in the SEI is still not well understood.…”

“…Recently, extensive efforts have been devoted to stabilizing Li anode by engineering a robust SEI mainly through electrolyte formulation [12][13][14][15][16] and artificial SEI. [17][18][19][20] However, the role of the structures and components of SEI has long been debated, and the transport mechanism of Li + ions in the SEI is still not well understood.…”

Guiding Fabrication of Continuous Carbon-Confined Sb2Se3 Nanoparticle Structure for Durable Potassium-Storage Performance

“…The mass loadings of DC− C/SS, PC−C/SS, and C−C/SS electrodes were controlled at ∼1 mg cm −2 (detailed mass loadings are displayed in Figure S2). The glass microfiber was used as a separator, and a metal potassium was used as 27,28 The cathode was precycled 5 times in the potassium half-cell at 0.2 A g −1 and then discharged to 2.0 V. Meanwhile, the anode was also precycled for 5 cycles. 29−31 3.…”

“…The mass ratio of the cathode and anode was controlled at ∼3.2:1. Because the formation of SEI/CEI (CEI = cathode electrolyte interface) caused irreversible capacity in the first cycle, the anode and cathode were precycled to eliminate the irreversible capacity in the first cycle. , The cathode was precycled 5 times in the potassium half-cell at 0.2 A g –1 and then discharged to 2.0 V. Meanwhile, the anode was also precycled for 5 cycles. − …”

Unveiling the Role of Li+ Solvation Structures with Commercial Carbonates in the Formation of Solid Electrolyte Interphase for Lithium Metal Batteries

“…However, their cycling performance is hindered by the growth of Li dendrites and low Coulombic efficiency (CE). [1][2][3][4][5] Solid electrolyte interphase (SEI) is considered to play crucial roles in repressing the growth of Li dendrites. [6][7][8][9] An ideal SEI film should have two major functions, i.e., anode passivation blocking side reactions between Li metal and electrolyte [10] and facilitating the transmission of Li + through the SEI layer.…”