Stable Rooted Solid Electrolyte Interphase for Lithium-Ion Batteries

Abstract

Metal oxide-based materials are attractive anode candidates for lithium-ion batteries (LIBs) because of their high theoretical capacity. However, these materials suffer from large volume expansion and poor stability of solid electrolyte interphase (SEI) during the charge–discharge process, casusing rapid capacity degradation. Herein, we report that Li3PO4-rooted and intact SEI in situ formed on the phosphate-modified SnO2/CNFs during cycling. The phosphate anions in the anode, could serve as the root to form Li3PO4 by bonding with Li ions and participate in the formation of the SEI, thus firmly anchoring and stabilizing the SEI layer. The rooted Li3PO4 and enriched LiF in the SEI could synergistically enhance the Li-ion diffusion, significantly reduce the volume expansion, and lead to ultrastable cycling performance over 1100 charge–discharge cycles at 1 A g–1. This work provides a new avenue for forming stable SEI rooted into the anode and inspires the development of interface engineering toward electrochemical energy storage.

Cross-Linking Network of Soft–Rigid Dual Chains to Effectively Suppress Volume Change of Silicon Anode

“…Each Nyquist plot delivers two semicircles (one in high frequency region and the other one in high-medium-frequency region) and one straight line in low frequency region. In the equivalent circuit, the semicircle in a high-frequency region is related to the SEI resistance impedance ( R SEI ), while the semicircle in the high-medium-frequency region is related to charge-transfer resistance impedance ( R ct ). ,, As shown in Figure g,h, the smallest R SEI of PAA-SS based Si electrode (32.3 Ω) indicates the fastest Li + ions diffusion by comparing with the R SEI of PAA-SS (35.5 Ω) and PVDF (38.1 Ω) based Si electrodes. The PAA-SS based Si electrode with the smallest R ct of 8.2 Ω demonstrates the fastest kinetics and the best interface stability.…”

“…6−8 However, issues like poor ion and electron conductivity of Si particles, pulverization of active materials, electrical contact loss, uncontrollable growth of solid electrolyte interphase (SEI) caused by the massive volume change during lithiationdelithiation processes, and subsequent inferior cycling reversibility severely impede its widespread industrial applications. 9 To address these issues, great efforts have been devoted to structural engineering of Si based materials or designing polymer binders with strong adhesion and excellent mechanical strength. As a critical component in the electrode materials, an ideal binder provides an adhesive network that can hold the active materials and conducting agents together on the current collector, which meanwhile guarantees continuous ionic/electronic transfer.…”

“…Developing high-capacity electrode materials is extensively considered as the key to meet the ever-growing demand for energy storage and conversion devices with high energy density. − Among the anode materials, naturally abundant silicon stands out as a promising candidate owing to its ultrahigh theoretical capacity of 4200 mAh/g. − However, issues like poor ion and electron conductivity of Si particles, pulverization of active materials, electrical contact loss, uncontrollable growth of solid electrolyte interphase (SEI) caused by the massive volume change during lithiation-delithiation processes, and subsequent inferior cycling reversibility severely impede its widespread industrial applications . To address these issues, great efforts have been devoted to structural engineering of Si based materials or designing polymer binders with strong adhesion and excellent mechanical strength.…”

“…Based on eqs and , we obtained D values, which are 1.46 × 10 –15 cm 2 /s, 6.63 × 10 –16 cm 2 /s and 2.28 × 10 –16 cm 2 /s for PAA-SS/Si, PAA/Si, and PVDF/Si electrodes, respectively. , The largest D value of the PAA-SS based Si electrode processes the largest Li-ion diffusion coefficient. The results also well account for the improved cycling and rate properties above.…”

Highly Enforced Rate Capability of a Graphite Anode via Interphase Chemistry Tailoring Based on an Electrolyte Additive

“…It has been known that modifying electrolyte components to regulate a protective solid electrolyte interphase (SEI) can boost the cyclic stability and rate capability of graphite anodes, − especially using electrolyte additives. , A robust and ionically conductive SEI can prevent direct contacts of the graphite anode with the electrolyte to suppress continuous electrolyte reduction decomposition and favor lithium-ion transportation. , Sulfur-containing electrolyte additives, such as 1,3-propane sultone (1,3-PS), , prop-1-ene-1,3-sultone (PES), diphenyl disulfide (DPDS), trimethylene sulfite (TMS), and 4-propyl­[1,3,2]­dioxathiolane-2,2-dioxide (PDTD), ,, are known as electrolyte additives for the construction of low-impedance interphases on graphite anodes . Inorganic lithium sulfites resulting from the reduction of these sulfur-containing additives contribute to the main components of SEI, thus favoring lithium-ion transportation in SEI and improving the rate capability of the graphite anodes.…”