Improving Electron and Ion Transport in Nano-Si Anodes through Integration with Conductive Nano-Metal-Organic Frameworks.

Abstract

Conductive metal-organic frameworks (c-MOFs) and nanosilicon (nano-Si) composites (Si-M-HHTP, M = Co, Ni, or Cu, HHTP = 2,3,6,7,10,11-hexahydroxytriphenylene) were synthesized using a single-step methodology to enhance the performance of nano-Si anodes in lithium-ion batteries. The promoting role of M-HHTP is reflected in the following: (i) extensive π-d conjugation enhances electrical conductivity; (ii) molecules stack into 2D rods for rapid Li⁺ transport; (iii) 2D rods construct a 3D structure to mitigate volume expansion. Electrochemical tests demonstrate that the 3D structure and conductive M-HHTP play a significant role in stabilizing the long-term cycling performance and enhancing rate capabilities. Moreover, the varying electrochemical properties observed in Si-Co-HHTP, Si-Ni-HHTP, and Si-Cu-HHTP can be attributed to the different electrochemical interactions between Co²⁺, Ni²⁺, and Cu²⁺ center coordination ions and Li⁺. The synergistic integration of nano-Si and c-MOFs presents a compelling approach for the development of high-performance lithium-ion batteries with high capacities, extended cycle lives, and superior rate performance.