Functional lithiophilic polymer modified separator for dendrite-free and pulverization-free lithium metal batteries

Ultralight PEDOT Functionalized Separators toward High‐Performance Lithium Metal Anodes

“…When turning back to an areal capacity of 5 mAh cm −2 at 5 mA cm −2 , the Li||PEDOT/PP||Li half‐cell delivers an overpotential of only ∼25 mV after 350 h. The ultra‐stable performance has hardly been achieved previously due to the sharp dendrite growth at high current density and areal capacity conditions. The rate capability of our Li||PEDOT/PP||Li half‐cell is superior to most of ever reported LMAs stabilized by different modifying separators or interlayer in consideration with achievable areal capacities and current densities (Figure 5d), [6–7,26,34–35,37,46] such as Au‐pillared rGO (2 mAh cm −2 , 0.5 mA cm −2 ), [6] Li 6.75 La 3 Zr 1.75 Ta 0.25 O 12 (LLZTO) coated separators (1 mAh cm −2 , 1 mA cm −2 ), [26] MnCO 3 /PP separator (1 mAh cm −2 , 5 mA cm −2 ), [34] exhibiting great promise for high‐performance LMAs at high current density.…”

“…Coating lithiophilic layers such as Ti 3 C 2 T x MXenes, [29] polydopamine/graphene, [30] nitrogen and sulfur codoped graphene, [31] g‐C 3 N 4 , [32] Mg, [33] and MgCO 3 [34] on the separators can homogenize Li + flux and facilitate dendrite‐free Li growth. Unfortunately, the mass loading of the most reported inorganic coating layers is high (>0.1 mg cm −2 ), which inevitably increases the electrolyte uptake and the weight of cells greatly [35–37] . Moreover, most modifying separators are prepared by vacuum filtration, [26,31–32] or magnetron sputtering methods, [33] which are tedious and complicated.…”

Surface-Functionalized Separator for Stable and Reliable Lithium Metal Batteries: A Review

“…In addition, it is an efficient and straightforward strategy to control the morphology and growing orientation of Li dendrite. Typically, the coating materials to functionalize the surface of polymer separators can be classified into five or six types: (a) thermally conductive materials [ 63 , 64 , 69 , 94 , 95 , 96 , 97 , 98 ], (b) metals [ 99 , 100 , 101 , 102 ], (c) polymers [ 103 , 104 , 105 , 106 , 107 , 108 ], (d) carbons [ 66 , 109 , 110 , 111 ], (e) metal oxides [ 67 , 88 , 112 , 113 , 114 , 115 , 116 , 117 , 118 , 119 ], and (f) others [ 120 , 121 , 122 , 123 , 124 ] ( Figure 3 ). For electrochemical evaluation, each separator coating material is laminated onto one side or both sides of the polymer separator, using the tape-casting method, physical vapor deposition, etc.…”

“…All these favorable features contributed to the improved electrochemical stability of Li metal anodes. Zhang et al formed a lithiophilic polymer layer comprising chitosan, poly(ethylene oxide) (PEO), and triethylene glycol dimethacrylate (TEGDMA) monomers over the Celgard separator via the electrospraying and polymerization process ( Figure 8 c) [ 105 ]. The synthesized layer enables uniform Li deposition on the anode, serves as an artificial SEI layer, and blocks the penetration of growing Li dendrites across the separator.…”

“…(Reproduced with permission from [ 104 ], Copyright 2012 WILEY-VCH) ( c ) Schematics to show the formation of a crosslinked 3D s-IP CTS-PEO-PTEGDMA layer. (Reproduced with permission from [ 105 ], Copyright 2020 Elsevier B.V.) ( d ) Fabrication of PDA/POSS modified-PE separators. (Reproduced with permission from [ 106 ], Copyright 2017 Elsevier) ( e ) Preparation of PEI(PAA/PEO) 3 -modified PE-Separator.…”