# Recent Advances in Lithiophilic Porous Framework toward Dendrite-Free Lithium Metal Anode
## 2 Metal-Based Li Host
### Nickel  
Similar to the 3D porous Cu, the 3D porous Ni has also been considered as a better alternative to any 2D Li host. The 3D structure incorporates the active anode material and provides efficient charge transport pathways. To improve the high rate capability, cyclability, and reduce the lithium amount, the foam lithium anode was prepared by Li electrodeposition on a Ni foam substrate [53]. Developing the honeycomb-like porous 3D Ni host on the Cu current collector via a hydrogen bubble dynamic template electrodeposition method has also been reported for stable Li and Na metal batteries [54]. However, the electrochemical deposition of lithium into the Ni foam host material for making Li/3D Ni composite anode, generally, leads to uneven Li deposition. Moreover, the batteries have to be dissembled, cleaned, and further assembling of a new battery is needed for pairing the resultant composite electrodes with the practical cathode materials. To address this complex and costly process, the development of a simple approach for encapsulating Li inside porous Ni or other scaffolds to develop Li-based composite anode is highly looked-for. [PERSON] et al., reported the thermal infusion strategy for pre-storing molten Li into stable 3D Ni foam to achieve a composite anode [55]. Figure 4a shows the schematic illustration of making the Li/3D Ni foam composite anode. Figure 4b,c shows the digital photos of Ni foam and the Li-Ni composite. Figure 4d-f shows the SEM images of Ni foam and Figure 4g-i shows the corresponding SEM images after molten Li infusion. The molten lithium fills the large pores of the Ni foam and Ni frameworks protuberance marked with the yellow arrow still exist, which implies that the architecture was well preserved. The composite anode with 26 mg cm\({}^{-2}\) loading of Li (50 wt % of composite) exhibited improved plating/stripping cycles for more than 100 cycles at 5 mA cm\({}^{-2}\) in the carbonate-based electrolyte. This can be attributed to the significant reduction in the interfacial resistance and smooth Li deposition. After 100 cycles of plating/stripping, the irreversible Li plating on bare Li shows deposition of 90 \(\upmu\)m thick Li, however, the Li-Ni composite anode does not show any thickness change. Moreover,  
Figure 3: Lithiophilic behavior on the Cu based porous framework. (**a**) Electronegativities of the various elements and \(\Delta_{x}\)G of elements/compounds reacted with the molten Li. Reproduced with permission from [50], Springer Nature, 2019. (**b**) Li wettability on the surface of Cu foil and VA-CuO-Cu substrate. Reproduced with permission from [41], John Wiley and Sons, 2018. (**c**–**e**) Schematic representation of the Li plating mechanism on planar Cu, VA-CuO-Cu, and nitrogen-doped VA-CuO and Cu\({}_{2}\)O-Cu. Reproduced with permission from [39], John Wiley and Sons, 2019. (**f**) Charge/discharge voltage profiles of the CuNW and CuNW-P collectors after 10 and 100 cycles at a current density of 2 mA cm\({}^{-2}\) for a total capacity of 1 mAh cm\({}^{-2}\) of Li. Reproduced with permission from [47], John Wiley and Sons, 2019.  
the full cell configuration with composite anode demonstrated better rate capability, low interfacial resistance, and lower voltage overpotential compared to the bare Li anode. To further address the issues of LMA and improve the electrochemical performance of LMBs, it is required to decorate the 3D Li host with lithophilic coatings. The lithophilic decoration in a porous Li host can greatly reduce the nucleation overpotential and guide the uniform Li deposition. To increase the affinity or Li wettability between the lithium and 3D porous host, various polymers [56], organic coating [50], elementary substances (such as Si nanoparticles [57], plated Ag [58]), oxides (such as NiO [59], CoO [60], Co\({}_{3}\)O\({}_{4}\)[61], ZnO nanoarrays (NAs) [62]), fluorides (NiF\({}_{\rm x}\)) [63], nitrides (Ni\({}_{3}\)N) [64], and sulfides (Ag\({}_{2}\)S) [65] have been utilized.