A multifunctional polyimide enabled high performance silicon composite anode materials for Li-Ion batteries

Carboxyl Function Group Introduced to Polyimide Binders for Silicon Anode Materials

“…The crystal structure information of PI/Si and PI-COOH/Si can be obtained from the XRD diffraction patterns. From Figure b, it can be clearly seen that the diffraction peaks at 28.4, 47.3, and 56.2°, which are crystal diffraction characteristic peaks of nano-silicon particles (compared with the standard card PDF #27-1402), indicating that the addition of polyimide shows no obvious effect on the crystal structure of Si during the preparation of the electrode sheet . The mechanical strength of polyimide as a novel silicon anode binder is a key factor affecting the electrode performance of silicon electrode batteries.…”

“…Before cycling, it can be seen that the nano-silicon particles in both the PI electrode and PI-COOH electrode are uniformly dispersed in the mixture. Such distribution can form pores of different sizes, which is conducive to lithium-ion transfer . After 20 cycles, it can be observed that the damage degree of the PI electrode is much higher than that of the PI-COOH electrode, implying that the ability of the PI-COOH binder to sustain the volume change of silicon particles has been much improved and then to maintain the electrode integrity to give favorable cycling performance.…”

“…From Figure 2b, it can be clearly seen that the diffraction peaks at 28.4, 47.3, and 56.2°, which are crystal diffraction characteristic peaks of nano-silicon particles (compared with the standard card PDF #27-1402), indicating that the addition of polyimide shows no obvious effect on the crystal structure of Si during the preparation of the electrode sheet. 42 The mechanical strength of polyimide as a novel silicon anode binder is a key factor affecting the electrode performance of silicon electrode batteries. The weak mechanical strength cannot sustain the huge volume change of the nano-silicon particles during the charge−discharge cycling, leading to the rupture of the electrode integrity and then rapid capacity decay with cycling.…”

Application of N-Doped Carbon–Silicon Oxycarbide Based on POSS Synthesis in Lithium-Ion Batteries

“…Figures S8 and illustrate the electrochemical performance of NSiOC integrated into coin cells. It can be widely recognized that the ion transport rate increases as the working temperature rises, which can affect the electrochemical performance of the materials. , However, the solvent dimethyl carbonate in the electrolyte may induce adverse effects and destroy the structure of the electrode material at high temperatures . Therefore, the typical maximum safe operating temperature for LIBs is about 60 °C.…”

“…The TGA and DSC curves of NSiOC (Figure S4) also show a 47.8% retention of the original mass, further indicating the approximate 50 wt % of N and C in the prepared NSiOC material. The existence of carbon coating and micropores could be beneficial in alleviating the volume expansion of silicon and the intercalation of lithium ions, − while nitrogen doping may enhance the conductivity of silicon-based composites and supply active sites by conjugating with the surrounding carbon atoms, which could in turn affect the performance of the thus-assembled LIBs. − …”