Low‐Temperature Preparation Copper‐Doped Nickel Chloride Cathode for Thermal Battery Overcomes the Energy‐Power Trade‐Off
Bin Yao, Licai Fu, Yufan Gui, Jiajun Zhu, Wulin Yang, Lingping Zhou
Abstract
Nickel chloride (NiCl 2 ) is a typical hexagonal layered semiconductor material with wide application. However, it is mainly restricted by complicated technological process within ultrahigh dehydration temperature. Utilizing copper doping, a sort of high purity and remarkable crystallinity NiCl 2 is fabricated using a simple low‐temperature calcination technique. The dehydration temperature is decreased from 600 to 400 °C because the adsorbed copper ions on NiCl 2 dihydrate surface can weaken NiO bond strength. Serving for thermal battery cathode, copper‐doped NiCl 2 exhibits remarkable discharge ability at 500 mA cm −2 , equipped with supernormal power density of 16.27 kW kg −1 and energy density of 717 Wh kg −1 simultaneously. Its energy density is increased by 28% compared to NiCl 2 . Copper doping optimizes thermodynamics process of discharge reaction and modifies local electronic structure of NiCl 2 . For copper‐doped NiCl 2 , the shift of Ni 3 d and Cl 3 p to lower energy level results in elevated redox potential, and the reduction of bandgap accelerates the carrier mobility, further promoting discharge degree. Utilizing metal ions dopant, this research surmounts the low‐temperature synthesis of NiCl 2 and addresses its inferior electrochemical performance, ensuring high energy‐power output. This will expand the application scenarios of NiCl 2 ‐based cathode materials.