NiTi-Layered Double Hydroxide@Carbon Nanotube as a Cathode Material for Chloride-Ion Batteries

Chloride-ion batteries (CIBs) are one of the promising candidates for energy storage due to their low cost, high theoretical energy density and high safety. However, the limited types of cathode materials in CIBs have hindered their development. In this work, a NiTi-LDH@CNT composite is prepared using a reverse microemulsion method and applied in CIBs for the first time. The specific surface area and the pore volume of the obtained NiTi-LDH@CNT composites can reach 266 m² g^-1 and 0.42 cm³ g^-1, respectively. Electrochemical tests indicate that the composite electrode delivers a reversible specific capacity of 69 mAh g^-1 after 150 cycles at a current density of 100 mA g^-1 in 0.5 M PP₁₄Cl/PC electrolyte. Ni²⁺/Ni³⁺ and Ti³⁺/Ti⁴⁺ valence changes during electrochemical cycling are demonstrated by X-ray photoelectron spectroscopy (XPS), while reversible migration of Cl^- is revealed by ex-situ EDS and ex-situ XRD. The stable layered structure and abundant valence changes of the NiTi-LDH@CNT composite make it an exceptional candidate as a cathode material for CIBs.