Restructuring NiO to LiNiO2: Ultrastable and reversible anodes for lithium-ion batteries

The discovery of active materials with long-term stability for lithium-ion batteries has always been a major challenge in the energy storage industry. Recently, by using the self-healing effect of hydrogen bonding in polymeric structures, researchers have developed a good strategy to prevent the pulverization of high-capacity anode materials, including those based on Si. However, these anode materials still show limited lifetimes owing to the self-degradation of their structure. In this study, we first demonstrated the self-healing effect resulting from the restructuring of NiO nanomaterials to LiNiO2 with a highly stable capacity for lithium storage applications. The investigated NiO nanosheet anode showed a high initial discharge/charge capacity of 1434/1113 mAh g−1, which gradually degraded during the initial lithiation process. However, this capacity could be recovered with an acceptable cyclic performance. The stable high capacity of ∼ 750 mAh g−1 at 0.5 A g−1 could be restored to ∼ 1200 mAh g−1 at 0.1 A g−1. The ex situ X-ray diffraction, scanning electron microscopy, transmission electron microscopy, and X-ray photoelectron spectroscopy analyses of the healable cell were carried out to analyze the structural transformation of NiO into LiNiO2. This material showed stable cycling performance at 1.0 A g−1 for 1000 cycles and at 10.0 A g−1 for 10,000 cycles along with an immediately restored capacity at 0.1 A g−1, demonstrating its significant potential for application as a long-term stable and high-capacity active material in lithium storage systems. These results indicated the future prospects of LiNiO2 materials and this work proposes a novel strategy for developing a permanent anode for lithium storage systems.