posted on 2021-11-11, 19:03authored byHyeon-Jae Noh, Min-Ho Lee, Byung Gon Kim, Jun-Ho Park, Sang-Min Lee, Jeong-Hee Choi
Three-dimensional (3D) hosts have
been identified as the most promising
anode design for lithium metal batteries (LMBs). This has been previously
demonstrated to be extremely effective at inhibiting the dendrite
growth by reducing the local current densities, resulting in stable
cycle performances. However, due to the complex synthetic procedures
and low lithium utilization ratios, the practical application of the
3D host anode still remains a challenge. To address these issues,
the current study reports the development and synthesis of a 3D-carbon-based
porous anode (3D-CPA) with a pore-size gradient using a practical
slurry-based process in which the pore sizes decrease from the top
to bottom layer. The pore-size gradient design accomplished using
carbon materials enables stable Li plating/stripping into the entire
inner pores without the formation of dendrites and also confirms the
high energy density of LMB. The as-prepared 3D-CPA with a pore-size
gradient also demonstrated a higher average coulombic efficiency of
98.8% (250 cycles) than other 3D-CPAs with mono-pore sizes. Additionally,
its symmetry cell had a prolonged lifespan of 660 hrs at 1 mAcm–2 (Li utilization ratio = 50%) and 680 hrs at 2 mAcm–2 (Li utilization ratio = 30%). Remarkably, a pouch
full cell composed of LiNi0.6Co0.2Mn0.2 (NCM622) with 4 mA h cm–2/as-prepared 3D-CPA retained
87.2% of its capacity after 100 cycles, using a carbonate-based electrolyte.
The current study, therefore, highly suggests the use of 3D host designs
for the fabrication of LMBs to achieve reversible Li reactions, leading
to long-term stability.