Pseudosolvent Guiding Ultralight V2CTx/Bacterial Cellulose with Fast Ion Diffusion Paths for High-Rate and High-Capacity Lithium Metal Anodes

Abstract

Practical application of Li metal anodes (LMAs) is restricted by growth of Li dendrites. Achieving uniform Li deposition with high practically available specific capacity is vital to obtain advanced LMAs. Herein, an ultralight V₂CT_x/bacterial cellulose (U-V₂CT_x/BC) foam with a volume density of 0.039 g cm⁻³ is guided by tertiary butanol to avoid restacking of both V₂CT_x and BC. The lithiophilic functional groups of V₂CT_x and BC synergistically induce the uniform Li nucleation. The loose stacking structure of the U-V₂CT_x/BC provides 3D ion channels for accelerating Li⁺ diffusion, homogeneous Li⁺ flux, as well as enough lithiophilic sites and interspace for Li deposition. As a result, the U-V₂CT_x/BC@Li exhibits superior stability of 2800 h at 5 mAh cm⁻² and 5 mA cm⁻² with an ultrahigh practically available specific capacity of 2040 mAh g⁻¹. Furthermore, full-cells paired with LiFePO₄ cathodes possess a remarkable capacity retention of 80.7% after 800 cycles at 1 C. Even at harsh conditions, the U-V₂CT_x/BC@Li||LiFePO₄ full-cells can also run 100 cycles at 0.3 C with a capacity retention of 84.9%. This work sheds light on both surface engineering and multiscale architecture design for the advanced LMAs with high practically available specific capacity.