Mechanochemical synthesis of Si/Cu3Si-based composite as negative electrode materials for lithium ion battery

Abstract

Mechanochemical synthesis of Si/Cu3Si-based composite as negative electrode materials for lithium ion battery is investigated. Results indicate that CuO is decomposed and alloyed with Si forming amorphous Cu-Si solid solution due to high energy impacting during high energy mechanical milling (HEMM). Upon carbonization at 800 °C, heating energy induces Cu3Si to crystallize in nanocrystalline/amorphous Si-rich matrix enhancing composite rigidity and conductivity. In addition, residual carbon formed on outside surface of composite powder as a buff space further alleviates volume change upon lithiation/delithiation. Thus, coin cell made of C-coated Si/Cu3Si-based composite as negative electrode (active materials loading, 2.3 mg cm−2) conducted at 100 mA g−1 performs the initial charge capacity of 1812 mAh g−1 (4.08 mAh cm−2) columbic efficiency of 83.7% and retained charge capacity of 1470 mAh g−1 (3.31 mAh cm−2) at the end of the 100th cycle, opening a promised window as negative electrode materials for lithium ion batteries.

An Investigation of Synthesis, Electrochemistry and Thermal Stability of Ball-milled Si-based Alloy Anodes in Lithium-ion Batteries

“…Consequently, the influence of NiO additions on the electrochemical performances of the Si-based electrodes can be investigated and discussed in isolation. The peaks related to Cu3Si become inconspicuous in the diffractograms of the three Si-CuO-NiO samples in Figure 2(b), implying a higher amorphization degree of Cu3Si [28,29]. NiSi2 is expected to be formed in this system with the diffraction peaks overlapping the ones of Si, and thus difficult to distinguish [32].…”

“…Considering the suitability of HEBM method for fabricating Si-M alloy anodes and large-scale production, a feasible solution is to use a metal oxide substituting for a pure metal element to alloy with Si. Under the condition of nonequilibrium driven by high mechanical energy [28], the processed Si-based composites are expected to produce metal silicides and amorphous Si oxides simultaneously. This HEBM approach has been evaluated recently by Chia-Chin Chang's group [28,29] and Peng Yu's group [30].…”

“…Under the condition of nonequilibrium driven by high mechanical energy [28], the processed Si-based composites are expected to produce metal silicides and amorphous Si oxides simultaneously. This HEBM approach has been evaluated recently by Chia-Chin Chang's group [28,29] and Peng Yu's group [30]. Both groups used Si and CuO as the raw materials to synthesize the Si-CuO composites.…”

“…Simultaneously, NiO is predicted to react with Si to form NiSi2 within a proper ratio range [20]; 2) Different from Cu3Si, NiSi2 is a Si-rich compound meaning there will be more active Si stored in the metal silicide when part of CuO is replaced with NiO. Correspondingly, the volume change of Si-based anodes would be effectively diluted [12]; 3) The ballmilled Si-based precursors often need to a post-treatment of coating a protective carbon layer for further enhancing the electrical conductivity, alleviating the volume change, stabilizing the SEI and prolonging life cycle [17,28,31]. However, this posttreatment is generally a high-temperature process [22] and a high-quality carbon coating requires ball-milled Si-based precursors to maintain the nanocrystalline/amorphous microstructure as much as possible [5,16].…”

Si-based Composite Anode for Li-ion Batteries with Enhanced Electrochemical Performance via CuCl2·2H2O Assisted Coating of PDA

“…In order to improve the performance of Si anode, one of the promising strategies is to make full use of synergistic effects of different aforementioned methods. Recently, Si-based anode materials with a unique structure of Si-MSi-M@C or Si-MSi@C (M = metal element) have been paid much attention and studied by many groups [17][18][19][20][21][22].…”