*2.1. Chemicals and Settings*

Barium nitrate (Ba(NO3)2, analytical grade) was purchased from Tianjin Shengao Chemical Reagent Co., Ltd (Tianjin, China). Titanium dioxide (TiO2, P25, chemically pure) was purchased from Degussa. Sodium hydroxide (NaOH, analytical grade) was purchased from Tianjin Komi Chemical Reagent Co., Ltd (Tianjin, China). Ethanol (analytical grade) was purchased from Tianjin Kaitong Chemical Reagent Co., Ltd (Tianjin, China). Distilled water was used in all the experiments. The drying oven (XMTD-8222) was purchased from Shanghai Jinghong Experimental Equipment Co., Ltd (Shanghai, China). The desktop high-speed centrifuge (H1850) was purchased from Hunan Xiangyi Centrifuge Co., Ltd (Xiangtan, China). The polymer (ceramic glue), a silicon-containing heat-resistant resin, was purchased from the IPINRU Chen Yu Technology Co., Ltd (Chengdu, China, Product No. CYN-01 with a curing temperature of ~220 ◦C). A silane coupling agent (KH550, NH2CH2CH2CH2Si(OC2H5)3) was purchased from Guangzhou Yuantai Synthetic Material Co., Ltd (Guangzhou, China). Al foils (thickness = ~12 μm, tensile strength ≥ 180 MPa, ductility ≥ 15%) were purchased from Shenzhen Kejing Star Technology Co., Ltd (Shenzhen, China).
