Electrolyte and anode‐electrolyte interphase in solid‐state lithium metal polymer batteries: A perspective

Abstract

The interest for solid-state lithium metal (Li •) batteries (SSLMBs) has been growing exponentially in recent years in view of their higher energy density and eliminated safety concerns. Solid polymer electrolytes (SPEs) are soft ionic conductors which can be easily processed into thin films at industrial level; these unique features confer solid-state Li • polymer batteries (SSLMPBs, i.e., SSLMBs utilizing SPEs as electrolytes) distinct advantages compared to SSLMBs containing other electrolytes. In this article, we briefly review recent progresses and achievements in SSLMPBs including the improvement of ionic conductivity of SPEs and their interfacial stability with Li • anode. Moreover, we outline several advanced in-situ and ex-situ characterizing techniques which could assist in-depth understanding of the anode-electrolyte interphases in SSLMPBs. This article is hoped not only to update the state-of-the-art in the research on SSLMPBs but also to bring intriguing insights that could improve the fundamental properties (e.g., transport, dendrite formation, and growth, etc.) and electrochemical performance of SSLMPBs. K E Y W O R D S anode-electrolyte interphase, solid polymer electrolytes, solid-state batteries, solid-state lithium metal polymer batteries This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.

Unprecedented Impact of Main Chain on Comb Polymer Electrolytes Performances

“…Important to note is that replacing P(H‐MPEGA) by P(CH 3 ‐MPEGMA) enables a significant enhancement in the cycle life of Li symmetric cells, e.g., 305 h (P(H‐MPEGA)) vs. 1135 h (P(CH 3 ‐MPEGMA)) (Figure 4a). Besides, the overall cell resistance ( R total ) estimated by Ohm law (Equation S4) could give useful information on the interfacial stability between SPE and Li metal electrode [19b] . For instance, the R total values for Li symmetric cells using LiFSI/P(CH 3 ‐MPEGMA) remain relatively stable after prolonged cycling (e.g., 365 Ω cm 2 (100 h) vs. 420 Ω cm 2 (1000 h)); while those for the cells using LiFSI/P(H‐MPEGA) gradually increase from 315 (100 h) to 410 Ω cm 2 after only 200 h. Furthermore, under static state, the Li symmetric cells with P(CH 3 ‐MPEGMA) show more stable resistances compared to those with P(H‐MPEGA) (e.g., 0 day, R i =55 Ω cm 2 for LiFSI/P(CH 3 ‐MPEGMA) vs. 45 Ω cm 2 for LiFSI/P(H‐MPEGA); 12 days, 69 Ω cm 2 for LiFSI/P(CH 3 ‐MPEGMA) vs. 61 Ω cm 2 for LiFSI/P(H‐MPEGA); 20 days, 72 Ω cm 2 for LiFSI/P(CH 3 ‐MPEGMA) vs. 56 Ω cm 2 for LiFSI/P(H‐MPEGA)), as displayed in Figures S14, S15.…”

Li‐Salt Doped Single‐Ion Conducting Polymer Electrolytes for Lithium Battery Application

“…This is the reason why they were early proposed as solid-state electrolytes (SSEs), [2][3][4] with renewed interest recently due to the possibility of using lithium metal anodes with SSEs and thereby improve DOI: 10.1002/macp.202100419 lithium battery energy density without compromising safety. [4,5] In practice their utilization as SSEs depends on the flexibility and motion of the polymer chains, which largely determines the ion transport and thereby ionic conductivity, and the Li-salt used, which affects the charge carrier concentration and nature. [6] One archetypical SPE is lithium bis(trifluoromethanesulfonyl)imide, LiTFSI, dissolved in poly(ethylene oxide), PEO, as suggested by Armand.…”

Revisiting the Preparation Progress of Nano‐Structured Si Anodes toward Industrial Application from the Perspective of Cost and Scalability

“…High‐energy density and long service life are the permanent pursuits for rechargeable batteries. [ 1–4 ] Lithium‐ion batteries (LIBs) play a key role in the development of electrical vehicles, [ 5–9 ] which is important for carbon neutrality. [ 10–18 ] Commercial graphite anode has reached the top ceiling due to the relative low theoretical capacity of 372 mAh g −1 , [ 19–21 ] which cannot satisfy the demand for the next‐generation anodes (>1000 mAh g −1 ).…”