Silicon (Si) is the most promising anode candidate for the next generation of lithium-ion batteries but difficult to cycle due to its poor electronic conductivity and large volume change during cycling. Nanostructured Si-based materials allow high loading and cycling stability but remain a challenge for process and engineering. We prepare a Si nanowires-grown-on-graphite one-pot composite (Gt-SiNW) via a simple and scalable route. The uniform distribution of SiNW and the graphite flakes alignment prevent electrode pulverization and accommodate volume expansion during cycling, resulting in very low electrode swelling. Our designed nano-architecture delivers outstanding electrochemical performance with a capacity retention of 87% after 250 cycles at 2C rate with an industrial electrode density of 1.6 g cm -3 . Full cells with NMC-622 cathode display a capacity retention of 70% over 300 cycles. This work provides insights into the fruitful engineering of active composites at the nanoand microscales to design efficient Si-rich anodes.

International audienceHerein, the novel concept of a solid-state electrode materials with ionic-liquid (IL) properties is presented. These composite materials are a mixture of electroactive matter, an electronic conductor, a solid-state ionic conductor and a polymeric binder. The approach of a solid-state ionic conductor combines the high safety of an IL with the nanoconfinement of such a liquid in a mesoporous silica framework, an ionogel, thus leading to a solid with liquid-like ionic properties. The same ionic conductor is also used as a solid-state separator to evaluate the properties of our solid-state electrode materials in all-solid-state batteries. Such a concept of a solid-state electrode material contributes to addressing the challenge of energy storage, which is one of the major challenges of the 21st century. The ionogel, along with its processability, allows a single-step preparation of the assembly of the solid-state electrode and solid-electrolyte separator and can be applied without specific adaptation to present, thick electrodes prepared by the widespread tape-casting technique. The filling of the electrode porosity by an ionogel is shown by elemental mapping using scanning electron microscopy, and is subsequently confirmed by electrochemical measurements. The ionogel approach is successfully applied without specific adaptation to two state-of-the-art, positive electroactive materials developed for future-generation lithium-ion batteries, namely LiFePO4 and LiNi1/3Mn1/3Co1/3O2