Manipulating Ion Transfer and Interface Stability by A Bulk Interphase Framework for Stable Lithium Metal Batteries

Abstract

Lithium metal batteries (LMBs) have attracted widespread concern as the next‐generation energy storage devices with high energy density. At the surface of lithium metal anodes (LMAs) toward electrolytes, lithium plating always competes with interfacial reactions. This makes interfacial reactions light shadow right behind lithium plating, leading to performance degradation. Herein, lithium plating is spatially decoupled from interfacial reactions by constructing a 3D solid electrolyte interphase framework (3D‐SEIF) inside LMAs. Spontaneous while mild chemical reactions between lithium metal and lithium bisfluorosulfonimide/lithium nitrate form the robust 3D‐SEIF, mainly consisting of LiF, Li3N, and LiNxOy. The built‐in 3D‐SEIF avoids electrolyte contact but enables the diffusion and reduction of Li+ ions in the bulk phase, thus isolating the plating sites and electrolyte contact interface. The 3D‐SEIF facilitates large granular plating and the generation of thin, inorganic‐rich SEI. When assembled with high‐loading LiNi0.6Co0.2Mn0.2O2 cathode (3 mAh cm−2), the cells present capacity retention of 92.0% after 130 cycles with barren electrolyte (≈30 µL) at 0.5 C. The conception of 3D inner interphase allows breaking the coupling of interfacial reactions with electrochemical reactions, which is taken for granted in electrochemical consortium. It also desires to inspire new thoughts to develop scalable solutions for the early industrialization of LMBs.

Dynamic Concentration of Alloying Element on Anode Surface Enabling Cycle‐Stable Li Metal Batteries

“…It is noted that a planar surface was also maintained for the Li‐Ag foil electrode after further extending the cycle times (Figure S9, Supporting Information), and the thickness of the reaction layer was only ≈21 µm after 100 cycles, outperforming the pure Li foil electrode with a loose electrode structure and a ∼70 µm‐thick reaction layer after 100 cycles. [ 44 ] The electrochemical impedance spectroscopy (EIS) of the cycled pure Li and Li‐Ag foil anodes was also measured after 100 cycles, which demonstrated a lower interface impedance for the Li‐Ag foil electrode than the pure Li electrode (Figure S10, Supporting Information). Maintaining thin and dense reaction layer with low interface resistance supported high Li utilization and suppressed side reactions for the Li‐Ag electrode.…”

Device‐Level Optimization of n‐Type Mg3(Sb, Bi)2‐Based Thermoelectric Modules toward Applications: A Perspective

“…Researchers have tried to pair the n ‐type Mg 3 (Sb, Bi) 2 with many different p ‐type materials, such as Bi 2 Te 3 , MgAgSb, CdSb, GeTe, and Zintl materials, as shown in Figure 6b. [ 37,51,73,76,77,79–83 ] In particular, a module incorporating MgAgSb was found to demonstrate remarkable robustness after thermal cycling over thirty thousand times. [ 77 ] Among the modules studied thus far, a temperature difference of 200–300 K can allow for an energy conversion efficiency of ≈8% in the medium‐temperature range, and a temperature difference of 400–480 K can result in an even greater energy conversion efficiency of ≈12% in the high‐temperature range.…”

“…For example, Zn 4 Sb 3 experiences a phase transition at 425 K, which makes it unsuitable for high‐temperature power generation in terms of structural reliability. [ 54,89 ] Half‐Heusler (NbFeSb) [ 90 ] and skutterudite (CoSb 3 ) compounds [ 91 ] have much lower coefficients of thermal expansion than n ‐type Mg 3 (Sb, Bi) 2 , [ 65,83 ] which may generate significant thermal stress in the associated device during high‐temperature operation due to substrate constraints. The widespread use of GeTe, PbTe, Bi 2 Te 3 , and TAGS (Ag 6.52 Sb 6.52 Ge 36.96 Te 50 ) is limited by either the toxicity or the high cost of their constituent elements.…”

“…The performance of p ‐type materials based on Mg 3 Sb 2 (i.e., Mg 1.594 Yb 0.2 Na 0.006 Zn 1.2 Sb 2 ) reported thus far still lag far behind that of their n ‐type counterparts. [ 83 ]…”

Fatigue-Free and Skin-like Supramolecular Ion-Conductive Elastomeric Interphases for Stable Lithium Metal Batteries

“…One routine way is to promote in situ formation of a stable SEI layer by optimizing the electrolytes, including sacrificial additives, highly concentrated electrolytes, and fluorinated electrolytes . Nevertheless, the so-formed SEI continuously grows by constantly consuming the electrolyte solvents, salt anions, or sacrificial additives in the electrolyte, making it difficult to modulate the composition and structure of the SEI. − Accordingly, the improvement in cycling stability by using a large excess of electrolyte inevitably compromises the energy density of batteries. Another approach is to replace the electrolyte-derived SEI by ex-situ formed artificial SEI layers such as inorganic materials (for example, Li 3 PO 4 , LiF, Li 2 S), organic polymers (for example, polyrotaxane- co -poly­(acrylic acid) (PR–PAA), P­(St-MaI), polydimethylsiloxane, and copolymer of poly­(ethylene glycol) methyl ether methacrylate and 2-[3-(6-methyl-4-oxo-1,4-dihydropyrimidin-2-yl)­ureido]­ethyl methacrylate), and organic–inorganic composites. − However, ionic insulation or poor ionic conductivity would definitely retard the Li + transfer across the interface, resulting in increased polarization and dendrite growth .…”