Preventing Structural Collapse and Thermal Runaway to Improve the Electrochemical Performance and Safety of LiNi_0.8Co_0.1Mn_0.1O₂ by a Negative-Thermal-Expansion Material of Al₂(WO₃)₄

Nickel-rich layered oxides such as LiNi0.8Co0.1Mn0.1O2 (NCM811) deliver high specific capacity and attract extensive interest for applications, but they still face some challenges of capacity fade and thermal runaway. Herein, NCM811 was modified with a cheap orthorhombic negative-thermal-expansion (NTE) material of Al2(WO3)4 to improve its electrochemical performance and safety by adjusting the heat, deformation, and interface via a simple strategy. The NCM811 material modified with 7 wt % Al2(WO3)4 (NA7) exhibits excellent electrochemical performance, thermal stability, and safety. Its reversible capacities can retain 162.0 and 171.5 mA h g–1 after 100 cycles at 25 and 60 °C, respectively, about 13.8 and 25.4% higher than those of the pristine NCM811. Simultaneously, the strain value after cycles and released heat from differential scanning calorimetry of NCM811 are decreased by Al2(WO3)4 about 50.6 and 45.3%, respectively. With the modification of Al2(WO3)4, the exothermic peak of NCM811 is up-shifted from 206.1 to 223.8 °C, while the side reaction, morphology breakdown, and structural damage are significantly prevented. According to multifarious results using various techniques, the enhancement mechanism of Al2(WO3)4 for NCM811 is proposed. It supplies a facile strategy to improve the performance and safety of energy materials using a cheap NTE material.