Enabling “lithium-free” manufacturing of pure lithium metal solid-state batteries through in situ plating

Inorganic solid‐state electrolyte (SSE) based Na‐metal batteries have received extensive attention in next‐generation lithium‐free energy storage systems with both high‐security and superior electrochemical performance. Herein, in contrast to the conventionally used polymer/ceramic/polymer sandwich electrolyte, an efficient green and scalable powder‐polishing synthetic method is developed to fabricate a pyrolyzed‐polyacrylonitrile modified Na super ionic conductor (NASICON) electrolyte to relieve polarization of integrated composite SSE and ameliorate interfacial contact between the electrolyte and the Na anode. Furthermore, introducing S in the preferable isotropous sulfurized polyacrylonitrile (SPAN) interlayer can trigger dehydrogenation and cyclization of polyacrylonitrile with chemically‐bonded short‐chain SS segments, which can bond with Na+ to redistribute the interfacial electric field and homogenize transported Na+ flux, leading to transition of Na deposition behavior from dendrite growth mode to lateral flat‐shape growth tendency. The conjugated polymer backbones possess delocalized radicals that can activate formed short‐chain sulfides to reconnect to the backbones, thus maintaining superior structural stability. Benefiting from the rational interfacial design, a record‐high value of 1.4 mA cm−2 for critical current density of Na/SPAN‐NASICON/Na cells is obtained. Moreover, SPAN is used as a cathode to assemble solid‐state Na/SPAN‐NASICON/SPAN Na‐organosulfur batteries, demonstrating superior capacity and cycling‐stability. The rational SPAN‐based structural design strategy may provide an avenue for potential application of solid‐state alkali metal batteries.

Section: Resultsmentioning

confidence: 99%

Isotropous Sulfurized Polyacrylonitrile Interlayer with Homogeneous Na⁺ Flux Dynamics for Solid‐State Na Metal Batteries

Miao

Wang

Sun

et al. 2021

“…[8,21,22] Li metal is an ideal anode that is hoped to be enabled by the development of all-solid-state technologies. [3,[23][24][25][26][27][28][29] Nirich layered oxides, LiMO 2 (M = Ni, Co, Mn, Al), which have been extensively investigated as cathodes for advanced LIBs based on LEs, [30][31][32][33][34][35][36] are also strong candidates for integration into practical ASLBs at scale. [18,37,38] Despite the use of SEs showing high Li + conductivities (>10 −3 S cm −1 ), electrochemical performances of layered oxide cathodes including LiCoO 2 and Li[Ni,Co,Mn]O 2 in ASLB cells have not been satisfactorily high in most previous reports.…”

Section: Introductionmentioning

confidence: 99%

Single‐ or Poly‐Crystalline Ni‐Rich Layered Cathode, Sulfide or Halide Solid Electrolyte: Which Will be the Winners for All‐Solid‐State Batteries?

Han

Jung

Kwak

et al. 2021

191

150

Moreover, sulfide SEs in contact with an inactive component of conductive carbon additives are oxidatively decomposed at the entire range of operating voltages of Li [Ni,Mn,Co]O 2 , leading to the lowered initial Coulombic efficiency (ICE) and gradual capacity fading upon cycling. [49] Owing to the incompressible feature of SEs, electrochemomechanical effects on the performance are also critical for allsolid-state batteries. [37,50,51] Even slight volumetric strains of a few percentages in LiMO 2 during charge and discharge induces loosening and/or loss of interfacial ionic contacts. [18,37,38,52] Moreover, very recently, our group demonstrated that commercial-grade LiNi 0.80 Co 0.10 Mn 0.10 O 2 , consisting of randomly oriented grains, was susceptible to severe disintegration of the secondary particles even at the initial charge and discharge due to the anisotropic volumetric strains, which led to poor electrochemical performance of low ICE and degradation of cycling retention. [37] In this regard, recently emerging research directions for cathodes in advanced LIBs based on LEs, the development of cracking-free single-crystalline Ni-rich layered oxides, [30,[53][54][55][56][57][58] could be in the same vein for the development of practical ASLBs.The recent discovery of halide SEs (Li 3 YX 6 (X = Cl, Br)) with Li + conductivities of over 10 −4 S cm −1 has opened new opportunities due to their excellent electrochemical oxidation stability (>4 V vs Li/Li + ) and much better chemical stability (more oxygen-resistant and no H 2 S evolution), compared to sulfide SEs, as well as deformability. [59,60] By exploration of the Li 3 YX 6 analogs, highly Li + conductive halide SEs of Li 3 InCl 6 (1.5 mS cm −1 ), [61] Li 3 ErCl 6 (0.33 mS cm −1 ), [62] Li 3 ScCl 6 (3.0 mS cm −1 ), [63,64] and Li 3−x M 1−x Zr x Cl 6 (M = Y, Er, 1.4 mS cm −1 ), [65] Li 2+x Zr 1−x Fe x Cl 6 (max. ≈ 1 mS cm -1 ) [66] were identified. By employing these new halide SEs, uncoated LiCoO 2 electrodes showed good electrochemical performance, which was attributed to their high electrochemical oxidation stability. [65,66,67] To date, reports on the application of halide SE for Ni-rich layered oxides are scarce. [64,66] The aforementioned advances in understanding the failure modes of Ni-rich layered oxides in terms of electrochemical and electrochemo-mechanical stabilities, advanced Ni-rich layered oxides with electrochemo-mechanically compliant microstructures, and new halide SEs led us, herein, to the rigorous investigation of all-solid-state cells with variations in Ni-rich layered oxides (single-crystalline LiNi 0.88 Co 0.11 Al 0.01 O 2 (single-NCA) vs conventional polycrystalline LiNi 0.88 Co 0.11 Al 0.01 O 2 (poly-NCA)) and SEs (halide SE Li 3 YCl 6 (LYC) vs conventional sulfide SE Li 6 PS 5 Cl 0.5 Br 0.5 (LPSX)). Notably, several critical counteracting pros and cons of two sets of NCAs and SEs, summarized in Figure 1a, pose intriguing questions on the type of factors that are critical from the viewpoint of designing ASLBs. First, compared to poly-...

“…[14] All the abovementioned limitations can be overcome or reduced if dendrite growth/breakage can be prevented during the deposition/ dissolution process. Many studies have been reported on the construction of dendrite-free metal anodes: a) fabrication of modified electrodes or metal substrate surfaces, [15][16][17][18][19][20][21][22][23][24] b) synthesis of new electrolytes, [25][26][27][28][29] c) use of solid electrolytes, [22,[30][31][32] and d) improvement of the electrode-electrolyte interface. [9,15,33,34] However, these studies have rarely focused on the properties, such as the stability of dendrites during charging and discharging, of dendrites.…”

mentioning

confidence: 99%

Self‐Healing Properties of Alkali Metals under “High‐Energy Conditions” in Batteries

Zhang

et al. 2021

With the development of high‐energy‐density metal batteries, dendrite growth has become a bottleneck for the further improvement of alkali metal electrodes. In this study, the self‐healing performance of dendrites under “high‐energy conditions” are predicted and verified. Initially, the driving force of self‐healing is analyzed based on surface energy. Theoretically, the activation energy for atom diffusion, which contributes to the resistance of self‐healing, is quantitatively calculated. Moreover, to illustrate self‐healing in Li, Na, and K electrodes, electrochemical curves, in situ optical images, and SEM images are obtained at different temperatures and current densities. Based on the results, it is concluded that K dendrites under “high‐energy conditions” (i.e., at high temperatures and high current densities) possess the highest self‐healing ability and reparability. Consequently, the self‐healing properties of alkali metals under high‐energy conditions are theoretically and experimentally examined and confirmed.