Three-dimensionally multiple protected silicon anode toward ultrahigh areal capacity and stability

Silicon (Si) is considered as one of the most promising candidates for next-generation lithium-ion battery (LIB) anode due to its high theoretical capacity. However, the drastic volume change of Si anodes during lithiation/ delithiation processes leads to rapid capacity fade. Herein, a three-dimensional Si anode with multiple protection strategy is proposed, including citric acid-modification of Si particles (CA@Si), GaInSn ternary liquid metal (LM) addition, and porous copper foam (CF) based electrode. The CA modified supports strong adhesive attraction of Si particles with binder and LM penetration maintains good electrical contact of the composite. The CF substrate constructs a stable hierarchical conductive framework, which could accommodate the volume expansion to retain integrity of the electrode during cycling. As a result, the obtained Si composite anode (CF-LM-CA@Si) demonstrates a discharge capacity of 3.14 mAh cm-2 after 100 cycles at 0.4 A g-1, corresponding to 76.1% capacity retention rate based on the initial discharge capacity and delivers comparable performance in full cells. The present study provides an applicable prototype of high-energy density electrodes for LIBs.

Automated summary

In this study, a three-dimensional silicon anode with multiple protection strategies was proposed, including citric acid-modification of silicon particles, GaInSn ternary liquid metal addition, and porous copper foam based electrode. This design effectively mitigates the volume change of silicon anode during lithiation/delithiation processes, improving the cycling stability and capacity retention rate of the battery.