Supercritical CO<sub>2</sub>‐Assisted SiO<i><sub>x</sub></i>/Carbon Multi‐Layer Coating on Si Anode for Lithium‐Ion Batteries
Rahmandhika Firdauzha Hary Hernandha, Purna Chandra Rath, B. Umesh, Jagabandhu Patra, Chih‐Yang Huang, Wen‐Wei Wu, Quanfeng Dong, Ju Li, Jeng‐Kuei Chang
Abstract
Abstract Supercritical CO 2 (SCCO 2 ), characterized by gas‐like diffusivity, low surface tension, and excellent mass transfer properties, is applied to create a SiO x /carbon multi‐layer coating on Si particles. Interaction of SCCO 2 with Si produces a continuous SiO x layer, which can buffer Si volume change during lithiation/delithiation. In addition, a conformal carbon film is deposited around the Si@SiO x core. Compared to the carbon film produced via a conventional wet‐chemical method, the SCCO 2 ‐deposited carbon has significantly fewer oxygen‐containing functional groups and thus higher electronic conductivity. Three types of carbon precursors, namely, glucose, sucrose, and citric acid, in the SCCO 2 syntheses are compared. An eco‐friendly, cost‐effective, and scalable SCCO 2 process is thus developed for the single‐step production of a unique Si@SiO x @C anode for Li‐ion batteries. The sample prepared using the glucose precursor shows the highest tap density, the lowest charge transfer resistance, and the best Li + transport kinetics among the electrodes, resulting in a high specific capacity of 918 mAh g −1 at 5 A g −1 . After 300 charge–discharge cycles, the electrode retains its integrity and the accumulation of the solid electrolyte interphase is low. The great potential of the proposed SCCO 2 synthesis and composite anode for Li‐ion battery applications is demonstrated.