Pine-Needle-Like Cu-Co Skeleton Composited with Li4 Ti5 O12 Forming Core-Branch Arrays for High-Rate Lithium Ion Storage.

High-performance of lithium-ion batteries (LIBs) rely largely on the scrupulous design of nanoarchitectures and smart hybridization of bespoke active materials. In this work, the pine-needle-like Cu-Co skeleton is reported to support highly active Li4 Ti5 O12 (LTO) forming Cu-Co/LTO core-branch arrays via a united hydrothermal-atomic layer deposition (ALD) method. ALD-formed LTO layer is uniformly anchored on the pine-needle-like heterostructured Cu-Co backbone, which consists of branched Co nanowires (diameters in 20 nm) and Cu nanowires (250-300 nm) core. The designed Cu-Co/LTO core-branch arrays show combined advantages of large porosity, high electrical conductivity, and good adhesion. Due to the unique positive features, the Cu-Co/LTO electrodes are demonstrated with enhanced electrochemical performance including excellent high-rate capacity (155 mAh g-1 at 20 C) and noticeable long-term cycles (144 mAh g-1 at 20 C after 3000 cycles). Additionally, the full cell assembled with activated carbon positive electrode and Cu-Co/LTO negative electrode exhibits high power/energy densities (41.6 Wh kg-1 at 7.5 kW kg-1 ). The design protocol combining binder-free characteristics and array configuration opens a new door for construction of advanced electrodes for application in high-rate electrochemical energy storage.