Stress Mitigation of Nanosilicon Anode to Achieve Energy ‐Dense and Highly‐Stable Full Cell

The expansion-induced stress concentration in a Si anode is successfully mitigated by constructing a porous structure out of a flexible Cu network that is metallurgically bonded to uniformly dispersed Si nanoparticles. Chemo-mechanical simulation and in (ex)-situ observation of structural evolution show how the high-strength flexible metallic network and metallurgical bonding interface affect the stress. AbstractNanosilicon (nano-Si) anode is subjected to significant stress concentration, which is caused by extrusion deformation of expanded Si nanoparticles with uneven distribution. The low-strength binder and adhesive interface are unable to withstand the stress, resulting in exfoliation and impeding the use of nano-Si anodes. This work aims to mitigate stress in a Si anode with flexible copper (Cu) skeletons that are metallurgically bonded to uniformly distributed Si nanoparticles. It is worth noting that the proposed porous Si-Cu anode exhibits improved high-load cycling performance and promising potential in the full cell, with an energy density of 463  Wh kg−1 at 0.5 C and retention of 81% after 500 cycles at 2 C. Chemo-mechanical simulation and in (ex) situ observation demonstrate that expansion stress is reduced and more evenly distributed in the anode due to uniform distribution of Si nanoparticles, flexible Cu skeletons, and adequate pores. More importantly, the stress is primarily distributed in the flexible Cu skeletons and bonding interface, preventing anode ex...
Source: Small - Category: Nanotechnology Authors: Tags: Research Article Source Type: research