Synergy of Si, Sn,\nand SWCNT Enables a Superior Mixed-Conductive\nSlurry-Coated Anode for All-Solid-State Lithium Batteries

All-solid-state lithium batteries (ASSLBs) with sulfide\nelectrolytes\nand high-capacity alloy anodes are among the most promising technologies\nfor achieving high safety and energy density. Herein, we demonstrate\na slurry-coated sheet-type electrode consisting of a 99.8 wt % Si–Sn\nhybrid active material and a 0.2 wt % single-walled carbon nanotube\n(SWCNT) binder, which could be used as a superior anode in ASSLBs.\nCompared to the typical composite powder electrode, the sheet-type\nSi–Sn electrode is free of electrolytes and extra carbon additives,\nenabling higher energy density at the electrode level but dominantly\ndepending on Li<sup>+</sup> diffusion and electron transport within\nthe Si–Sn active material. It is identified that the lithiated\nSi–Sn hybrid is an excellent mixed ion-electron conductor that\novercomes insufficient electronic or ionic conductivities of lithiated\nSi and Sn individuals. In addition, using SWCNT instead of ordinary\npolymer binders can improve electrode integrity and preserve electrical\nconnections during cycling. When paired with a LiNi<sub>0.8</sub>Co<sub>0.1</sub>Mn<sub>0.1</sub>O<sub>2</sub> (NCM811) cathode (a mass loading\nof 11.3 mg cm<sup>–2</sup>), the Si–Sn–SWCNT||NCM811\nfull cell shows stable cycling for more than 200 cycles at 0.5C with\na capacity retention of 85.9%. Even at a high NCM811 loading of 36.4\nmg cm<sup>–2</sup>, the full cell exhibits a considerable capacity\nretention of 85.0% (50 cycles, 0.1C) and a maximum areal capacity\nof 5.8 mAh cm<sup>–2</sup>. This work provides an industry-compatible\nmethod to produce high-performance alloy anodes for ASSLBs.