High performance all-solid-state thin-film supercapacitor enabled by nano‑carbon enriched SiCO electrode and doping strategy optimized LiPON electrolyte

All-solid-state supercapacitors (ASSSCs) represent longer cycling life, higher safety and improved chemical stability compared to liquid electrolyte-based supercapacitors . However, relatively low energy density and high interfaical resistance of electrode/electrolyte are still major obstacles for developing high performance ASSSCs. Herein, a high performance ASSSCs is realized based on nano‑carbon silicon oxycarbide (SiCO) electrode and lithium phosphorous oxynitride (LiPON). First-principles calculations reveal that high concentration of carbon network in SiCO impedes volumetric expansion and leads to higher formation energy of the interface, doping Al in LiPON improves ion diffusion and charge transfer capability of the interface, thus enhancing electrical conductivity and cycling performance of ASSSC. The ASSSC device with the optimal carbon content of SiCO and doping strategy improved LiPON exhibits higher capacity retention of 80.88 % after 1000 cycles life. In addition, a small impedance of 172.8 Ω for SiCO/LiAlPON interface is achieved, which is obviously lower than the result of 310 Ω for SiCO/LiPON interface. This work offers an experimental and computational framework for developing novel nanomaterials-based ASSSCs. • An experiments-first principles combined framework is proposed for ASSSC. • The optimal carbon morphology and doping strategy leads to excellent performance. • An obviously smaller impedance of 172.8 Ω for SiCO/LiAlPON interface is achieved. • High carbon concentration of SiCO leads to higher formation energy of interface. • Doping Al in LiPON improves ion diffusion and cycling performance of ASSSC.