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LiNi0.88Co0.1Al0.02O2(NCA) is attractive for high-energy batteries, but phase transition and side reactions leave large volume change and thermal runaway. In order to address the drawbacks, orthorhombic Al2(WO4)3, a cheap anisotropic negative thermal expansion material, was synthesized and adopted to modify NCA, and its effects on the electrochemical performance and safety of NCA were investigated using multifarious techniques. Al2(WO4)3can greatly improve the rate performance, cyclability at different temperatures, thermal stability, and interface behavior and intensify charge transfer as well as decline the deformation and side reactions of NCA. The discharge capacity of the NCA modified with 5 wt % Al2(WO4)3reaches 170.0 mA h/g at 5.0 C and 25 °C. After 100 cycles, the values of this electrode at 1.0 C and 25 °C and at 3.0 C and 60 °C are 164.2 and 148.7 mA h/g, respectively, much higher than those of the pure NCA under the same conditions. Moreover, Al2(WO4)3declines the byproducts and cation mixing and decreases the released heat, strain, and charge-transfer resistance after cycles of NCA about 37.1, 33.0, and 32.8%, respectively. The improvement mechanism is discussed. It opens an effective avenue for the applications of energy materials by simultaneously adjusting heat, structure, interface, and deformation.

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)4to 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–1after 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)4about 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)4for NCM811 is proposed. It supplies a facile strategy to improve the performance and safety of energy materials using a cheap NTE material.

Rechargeable lithium-oxygen cells are promising because of their high theoretical energy density, but they still face some challenges for applications. To address the problems like large polarization and poor reversibility of oxygen electrodes, a reversible binder-free three-dimensional (3D) hierarchical porous cathode was constructed by electrodepositing perovskite cerium orthoferrite CeFeO3nanoparticles on flexible graphite foam (GF) via a facile way. It exhibits a low overpotential for oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) and delivers a high initial discharge capacity of 11.53 mAh·cm–2at 0.04 mA·cm–2, about 10 times that of pristine GF. The charge transfer resistance of GF is reduced by about 81% by CeFeO3, while the ORR and OER peak current densities are increased by 982 and 1167%, respectively. Furthermore, CeFeO3can efficiently suppress the side reactions of GF to reduce the overpotential and improve the cycle performance during cycles. Multifarious results reveal that the superior catalytic activities of CeFeO3and hierarchical porous structure are responsible for the excellent electrochemical performance. It paves a novel way to develop a multifunctional electrocatalyst for oxygen electrodes by combining catalysis and microstructure using a green electrochemical method.

More measures are being developed to enhance the electrochemical stability of single‐crystal LiNi0.6Co0.2Mn0.2O2(NCM622), but few focus on improving the stability of NCM622 through heat and deformation management. Herein, a negative‐thermal‐expansion (NTE) material of zirconium tungstate ZrW2O8is adopted to modify NCM622 via a facile method, and the sample with a proper content of ZrW2O8exhibits superior cycle performance and rate capability. The capacity retention ratio of modified NCM622 is 86.2% (from 193.6 to 166.8 mAh g−1) after 100 cycles at 2  C between 2.8 and 4.5  V at 60 °C, whereas that of the pristine NCM622 is only 77.5% (from 183.8 to 142.4 mAh g−1). According to various analysis results, the possible enhancing mechanisms of ZrW2O8for NCM622 are discussed. It is an alternative for the remaining good structure of energy materials using NTE materials. Benefitting from the volume shrinkage of negative‐thermal‐expansion material ZrW2O8at high temperature, the bulk structure of NCM622 is maintained well from the destruction induced by thermal expansion, which is demonstrated by the result that the capacity retention of modified NCM622 after 100 cycles at 60 °C is enhanced from 77.5 to 86.2%.