Fig 1

(a) The specific energy comparison between Li ion battery and Li metal battery; (b) the main problems of Li anode in Li metal battery."

Fig 2

(a) Schematic of fabricating layered rGO and Li composite electrode 44. (b) Schematic of inducing Li deposition via N-doped graphene 45. (c) Schematic of fabricating Li and graphene foam modified by metallic oxide nanoarrays 46. (a) Adapted from Ref. 44. Copyright 2017, Springer Nature. (b) Adapted with permission from Ref. 45. Copyright 2016, Wiley-VCH. (c) Adapted with permission from Ref. 46. Copyright 2018, Wiley-VCH."

Fig 3

(a) Schematic of inducing Li deposition via Ag nanoparticle modifying carbon nanofibers (CNFs) 59. (b) Schematic of fabricating Li@CC-CNTs composite electrode 62. (c) Schematic of TiN-VN@CNFs applied for Li anode and sulfur cathode 63. (a) Adapted with permission from Ref. 59. Copyright 2017, Wiley-VCH. (b) Adapted with permission from Ref. 62. Copyright 2018, Wiley-VCH. (c) Adapted with permission from Ref. 63. Copyright 2019, Wiley-VCH."

Fig 4

(a) Schematic of synthesizing Li-Ni composite and the corresponding optical photograph 86. (b) Schematic of fabricating Cu nanowires and the effects of regulating Li ions flux between planar and 3D porous Cu 95. (c) Schematic of inducing Li nucleation between Cu nanofibers and Al coated Cu nanofibers 99. (a) Adapted with permission from Ref. 86. Copyright 2017, Wiley-VCH. (b) Adapted from Ref. 95. Copyright 2015, Springer Nature. (c) Adapted with permission from Ref. 99. Copyright 2019, Wiley-VCH."

Fig 5

(a) Schematic of infusing molten Li into CNTs cluster 103. (b) Schematic of Li and ZIF-8 based carbon material composite electrode and the corresponding Li-Zn binary phase diagram 106. (c) Schematic of fabricating LAN electrode derived Li powder, AlN and CNT powder 109. (a) Adapted with permission from Ref. 103. Copyright 2017, Royal Society of Chemistry. (b) Adapted with permission from Ref. 106. Copyright 2018, Wiley-VCH. (c) Adapted with permission from Ref. 109. Copyright 2020, American Chemical Society."

Table 1

The cycling performance comparison of Li symmetrical cells with different matrix."

Fig 6

(a) The effect schematic between solvent molecule and ions in conventional, high-concentrated and diluted concentrated electrolyte. (b) Schematic of the effect of highly fluorinated interphase in Li metal battery, (c) the full battery performance comparison between conventional electrolyte and F-rich electrolyte, (d) the LUMO and HOMO energy comparison between EC, DMC and LiFSI. (a) Adapted from Ref. 125. Copyright 2019, Springer Nature. (b–d) Adapted from Ref. 126. Copyright 2017, Elsevier."

Fig 7

(a) Schematic of FEC additive protecting Li metal anode and the LUMO energy comparison between EC, FEC and DEC 147. (b) The sectional image of Li anode after cycling using conventional electrolyte and FEC/LiNO3 electrolyte, and the corresponding performance comparison full battery 153. (c) Schematic of inducing Li deposition via CsPF6 additive and the corresponding morphologies after cycling without and with CsPF6 28. (a) Adapted with permission from Ref. 147. Copyright 2017, Wiley-VCH. (b) Adapted with permission from Ref. 153. Copyright 2018, Wiley-VCH. (c) Adapted with permission from Ref. 28. Copyright 2013, American Chemical Society."

Fig 8

(a) Schematic of fabricating LiF protection layer and the corresponding morphology structure 170. (b) Schematic of Li deposition on the bare Li and MClx (M = In, Zn, Bi, As) protected Li, the corresponding sectional structure and full battery performance comparison 176. (c) Schematic of the fabrication process and effect of Li2S protection layer 183. (d) Schematic of Li-PAA protecting Li metal anode 194. (a) Adapted with permission from Ref. 170. Copyright 2017, American Chemical Society. (b) Adapted from Ref. 176. Copyright 2017, Springer Nature. (c) Adapted with permission from Ref. 183. Copyright 2019, Wiley-VCH. (d) Adapted with permission from Ref. 194. Copyright 2018, Wiley-VCH."

Table 2

The cycle performance comparison of Li symmetrical cells with different artificial SEI."

Fig 9

Schematic of the Li dendrite growth process in Li metal batter using normal separator (a) and FNC-coated separator (b) 208. Adapted from Ref. 208. Copyright 2017, Springer Nature."

Fig 10

(a) Schematic of solid Li metal battery using SPEs, ICEs and ASE as electrolyte 222. (b) Schematic of Li-C composite on LLZO electrolyte, the corresponding optical image and the full battery performance using LFP as cathode 223. (c) Schematic of Li deposition behavior and morphology structure in PLL solid electrolyte and liquid electrolyte 224. (d) Sectional structure and schematic of solid Li metal battery using Ag/C as Li-free anode 227. (a) Adapted with permission from Ref. 222. Copyright 2018, American Chemical Society. (b) Adapted with permission from Ref. 223. Copyright 2019, Wiley-VCH. (c) Adapted from Ref. 224. Copyright 2014, National Academy of Sciences. (d) Adapted from Ref. 227. Copyright 2020, Springer Nature."

Table 3

The cycle performance comparison of solid-state Li metal batteries."