Solvent-free (SF) anodes with different carbon materials (graphite, hard carbon, and soft carbon) were fabricated to investigate the stability of different anodes with polytetrafluorethylene (PTFE) degradation. The graphite anode with large volume variation during the charge/discharge process showed poor cycle life performance, while hard carbon and soft carbon with low-volume expansion showed good cycle life. The SF hard carbon electrodes with a high loading of 10.7 mg/cm2 revealed good long-term cycling performance similar to conventional slurry-casting (CSC) electrodes. It demonstrated nearly 90% capacity retention after 120 cycles under a current of 1/3 C with LiNi0.5Co0.2Mn0.3O2 (NCM523) as cathode in coin cell. The rate capability of the high-loading SF electrodes also is comparable to the CSC electrodes. The high stability of SF hard carbon and soft carbon anodes was attributed to its low-volume variation, which could maintain their integrity even though PTFE was defluorinated to amorphous carbon irreversibly. However, the reduced amorphous carbon cannot tolerate huge volume variation of graphite during cycling, resulting in poor stability.

The capability of battery materials to deliver not only high lithium storage capacity, but also the ability to operate at high charge/discharge rates is an essential property for development of new batteries. In the present work, the influence on the charge/discharge rate behaviour of substoichiometric concentrations of phosphorus (P) in silicon (Si) nanoparticles was studied. The results revealed an increase in rate capability as a function of the P concentration between 0 and 5.2 at %, particularly during delithiation. The stoichiometry of the nano-particles was found to strongly affect the formation of the Li 3.5 Si phase during lithiation. Cyclic stability experiments demonstrated an initial increase in capacity for the SiP x materials. Galvanostatic intermittent titration technique and electrochemical impedance spectroscopy demonstrated the increased lithium diffusivity with inclusion of P. Density functional theory and ab initio molecular dynamics were deployed to provide a rationale for the electrochemical behaviour of SiP x .

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Interactions between electrolyte constituents and active materials strongly influence the capacity, energy density, and cycling stability of energy storage devices. In this study, the role of electrolyte dielectric on the...

Solvent‐free graphite anode is fabricated successfully with the synergistic effect of polytetrafluorethylene (PTFE) and polyvinylidene fluoride (PVDF). PTFE acts as a processing aid reagent to form a self‐supporting electrode film, while PVDF acts as a functional binder when PTFE decomposes in the first lithiation process. The solvent‐free graphite electrode with high loading of 15 mg cm−2 shows good stability with more than 95% capacity retention after 50 charge/discharge cycles under the current of 0.23 mA cm−2. Electrodes with extra high loading of 27 mg cm−2 (8.2 mAh cm−2) are fabricated and show good stability. Initial coulombic efficiency increases to 89% after prelithiation in the full cell with lithium iron phosphate as cathode. The capacity retention of full cells is more than 80% after 110 cycles under the current of 0.7 mA cm−2 in coin cells. The roll‐to‐roll production makes the procedure compatible with current commercial lithium‐ion batteries production lines, exhibiting great potential for upscaling production.