Facile Lithium Densification Kinetics by Hyperporous/Hybrid Conductor for High‐Energy‐Density Lithium Metal Batteries

Abstract Lithium metal anode (LMA) emerges as a promising candidate for lithium (Li)‐based battery chemistries with high‐energy‐density. However, inhomogeneous charge distribution from the unbalanced ion/electron transport causes dendritic Li deposition, leading to “dead Li” and parasitic reactions, particularly at high Li utilization ratios (low negative/positive ratios in full cells). Herein, an innovative LMA structural model deploying a hyperporous/hybrid conductive architecture is proposed on single‐walled carbon nanotube film (HCA/C), fabricated through a nonsolvent induced phase separation process. This design integrates ionic polymers with conductive carbon, offering a substantial improvement over traditional metal current collectors by reducing the weight of LMA and enabling high‐energy‐density batteries. The HCA/C promotes uniform lithium deposition even under rapid charging (up to 5 mA cm−2) owing to its efficient mixed ion/electron conduction pathways. Thus, the HCA/C demonstrates stable cycling for 200 cycles with a low negative/positive ratio of 1.0 when paired with a LiNi0.8Co0.1Mn0.1O2 cathode (areal capacity of 5.0 mAh cm−2). Furthermore, a stacked pouch‐type full cell using HCA/C realizes a high energy density of 344 Wh kg−1 cell/951 Wh L−1 cell based on the total mass of the cell, exceeding previously reported pouch‐type full cells. This work paves the way for LMA development in high‐energy‐density Li metal batteries.

Total Hildebrand parameter, δ t , can be calculated from the following equation: Table S1.Hansen solubility parameters and the calculated solubility parameter distance.RHSP values are calculated based on the water (solvent) and other nonsolvents.*N/M: Not mentioned.

Figure S3 .
Figure S3.(a) Nyquist plots of various HCA/C with different nonsolvent, soaked in the electrolyte.(b) The voltage response of different substrates to 5 mA applied current using stainless steel (SS) blocking electrodes.(c) Comparisons of electronic conductivity and electrolyte-impregnated ionic conductivity for various HCA/C with different nonsolvent.

Figure S4 .
Figure S4.(a) Nyquist plots comparison of various electrode, soaked in the electrolyte with blocking cell.(b) electrolyte-impregnated ionic conductivity of PVA polymer film by spin coating process and PVA architecture by NIPS process

Figure S6 .
Figure S6.SEM images of an interface between HCA/C and CNT film.

Figure S7 .
Figure S7.(a) Voltage profiles of lithium electrodeposition on Cu and in HCA/C until reaching to the areal capacity of 5 mAh cm -2 .SEM images of (b-g) HCA/C and (h-m) Cu after plating of (b, e, h, k) 1 mAh cm -2 , (c, f, i, l) 3 mAh cm -2 , and (d, g, j, m) 5mAh cm -2 of deposited Li under the current density of 0.5 mA cm -2 .

Figure S8 .
Figure S8.Contact angle observation just after physical contact between of electrodes (Cu and HCA/C) and electrolyte droplet to confirm the comparison of electrolyte impregnation.

Figure S11 .
Figure S11.(a) SEM images before and after lithium deposition of 5 mAh cm -2 on 3D Cu mesh under current densities of 1 mA cm -2 and 5 mA cm -2 .(b) Cycling performance of an asymmetric cell with 3D Cu mesh at high current density of 5 mA cm -2 .

Figure S13 .
Figure S13.Normalized TOF-SIMS depth profiles of characteristic fragments sputtered from (a) HCA/C and (c) Cu after 30 cycles.3D variation of the TOF-SIMS intensity related to the corresponding characteristic fragments from (b) HCA/C and (d) Cu after 30 cycles.((i) Organic SEI layer, (ii) Inorganic SEI layer & Li metal, and (iii) Substrate or subsrate-Li metal)

Figure S15 .
Figure S15.SEM images of HCA/C to verify the feasibility of thickness control depending on the amounts of lithium accommodation in HCA.

Figure S21 .
Figure S21.SEM images of (a) HCA/C-Li and (b) Cu-Li after 70 cycled in the full cells.

Figure S22 .
Figure S22.(a) Cycle efficiency for lithium electrodeposition/dissolution on Cu and in HCA/C under the current density of 1 mA cm -2 for areal capacity of 1 mAh cm -2 .(b) Cycle retention of Cu||NCM811 and HCA/C||NCM811 with high-loaded cathode (1 C = 5.0 mA cm -2 ).

Figure S23 .
Figure S23.The weight comparison of Cu, SWCNT film, and HCA/C in 16pi disk.

Figure S24 .
Figure S24.Pie chart comparison of weight contribution for building the stack pouch full cells.

Figure S26 .
Figure S26.Photograph images of as-assembled stack pouch full cell and total weight measurement of the pouch cell.

Figure S27 .
Figure S27.SEM images of HCA/C after double side casting of HCA.

Table S2 .
Comparison of cathode type, cathode mass loading, current density, and N/P ratio of cointype full cell fabricated in this work and previously reported works.

Table S3 .
Summarized table of cell components in the stack pouch full cell.

Table S4 .
Measured and calculated cell parameters of the stack pouch full cell.

Table S5 .
Comparison of the pressure, capacity, and energy density of pouch full cell fabricated in this work and previously reported high-energy-density pouch full cells (Li-free denotes configurations where the anode initially contains no reserve lithium).