The LiNi 0.8 Co 0.1 Mn 0.1 O 2 (NCM) electrodes are successfully prepared by 3D gel printing (3DGP) technique in this study. The results show that when the slurry with 45 % solid content was squeezed out of the needle, the viscosity of the printing slurry was 1.54 Pa s at the shear rate of 660 s −1 , which shows that the printing slurries are suitable for 3DGP. At the same time, when the inner diameter of the printing needle is 0.25 mm, the air pressure is 0.40 MPa and the printing speed is 4.60 mm s −1 , the structure of printing electrode is complete. The electrochemical measurement results show the printed NCM electrode with 231 μm printing line spacing has a higher capacity of 169.80 mAh g −1 at 4C, a specific capacity of 103.9 mAh g −1 at 1C after 500 cycles and an energy density of 232 Wh kg −1 , which shows that the high specific capacity and good cycling stability exhibited by NCM electrodes fabricated by 3DGP.
Incorporating high valence dopants, such as W 6+ and Mo 6+ has been verified to be effective for tuning the microstructure and grain boundary of polycrystal Ni-rich cathode. However, the hindered consolidation of primary particles induced by dopants during lithiation calcination limits the utilization of those dopants to crystalize single-crystal Ni-rich cathodes with stabilized lattice and surface. Herein, high performance single crystal LiNi 0.84 Co 0.11 Mn 0.05 O 2 cathode with Al 3+ and W 6+ regulated lattice and boundary phase was construed based on commercial process with two-step calcination process containing separated lithiation and crystallization. The introduction of appropriate amount of Al 3+ in the first lithiation calcination of 6 h endows the bulk of crystalline with enhanced lattice stability, while the incorporation of W 6+ with stoichiometrical LiOH in the secondary crystallization calcination of 6 h renders uniformly distributed surface layer without hampering the growth of single-crystal. With the Al 3+ doped bulk lattice, W 6+ doped subsurface region and hetero-epitaxially grown Li 2 WO 4 , the cathode infused by two-step calcination exhibits high discharge capacity, rate performance, and cycling stability. Specifically, the modified LiNi 0.84 Co 0.11 Mn 0.05 O 2 exhibits exceptional capacity retention, maintaining 88.98% of its initial capacity after 200 cycles at a rate of 1 C within a voltage window of 2.7–4.3 V at a temperature of 25 °C in half-cell. This performance is markedly superior to the capacity retention of 72.96% observed for pristine cathode. Even when subjected to a stringent test after 200 cycles at the same rate, the modified cathode sustains an impressive capacity retention of 82.41% at an elevated cut-off voltage of 4.5 V and a temperature of 30 °C.
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