Cu3Si enhanced crystallinity and dopamine derived nitrogen doping into carbon coated micron-sized Si/Cu3Si as anode material in lithium-ion batteries

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

“…However, the cycling stability of pristine Si is the poorest with a capacity retention of only 20.7% after 100 cycles (Figure 6(b)). When a 10% addition of CuO via ball-milling into Si bulk, it is found to significantly improve the cycling performance, giving 74.1% capacity retention after 100 cycles, consistent to the previous reports [28,29]. As the CuO content further rises to 23.5%, the cycle performance of Si76.5CuO23.5 unexpectedly becomes worse showing a 100 th -cycle capacity retention of 59.6 %.…”

“…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].…”

“…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].…”

“…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.…”

Cu3Si-Modified Silicon Nanoparticles Encapsulated within SiOx and Hollow Carbon for Lithium-Ion Battery Anodes

“…However, carbon leads to large irreversible capacity loss and is easily destroyed by repeated expansion and contraction of silicon due to its weak mechanical strength. − Metal silicides (Cu x Si, − Ni x Si, , or Mn x Si) have excellent toughness, conductivity, high binding force with silicon, and small irreversible capacity for which Si/C composites have been widely enhanced by various metal silicides. Deng et al prepared Si@NiSi 2 /Ni/C composites by a coprecipitation and pyrolysis process, which delivered significantly improved performance compared to its control samples of NiSi 2 /Si and Si/C anode used in LIBs that simply compound with metal silicide or carbon.…”