Simultaneous enhancement of ordered layered structure and inhibition of micro-cracks via porous structure to improve stability for Ni-rich cathode

On account of low cost and high energy density, Ni-rich cathode materials are competitive candidates for next-generation Lithium-ion batteries for electric vehicles and portable electronic devices. Nevertheless, the structural degradation of a Ni-rich cathode, which sustained Li+/Ni2+ disorder and the build-up of mechanical stress during a long cycle, has been a colossal challenge. Herein, LiNi0.8Co0.1Mn0.1O2 with porous structure has been synthesized successfully using a controllable, efficient, and scalable co-precipitation method. The porous precursor was prepared by co-precipitation of transition metal ions with hydroxide and carbonate from the hydrolysis of sodium carbonate. After pre-calcination, the precursor transforms into porous oxide with high content of Ni3+, which is beneficial to prepare LiNi0.8Co0.1Mn0.1O2 with reduced Li+/Ni2+ disordering. Abundant pores inside cathode material can effectively reduce stress accumulation caused by anisotropic lattice expansion and shrinkage, further decrease the generation of cracks and the incidence of adverse side reactions, keeping electrode intact over long cycles. The capacity retention thus reaches up to 90.5 % after 200 cycles at 0.5 C (1C = 200 mA g−1). Multiple test systems and finite element simulation analysis show that well-ordered porous cathode material from homogeneous precursors has a dual effect: it provides buffer space to relieve mechanical stresses and reduces Li+/Ni2+ mixing. This work provides a user-friendly and mass-producible method to prepare controllable structural precursor.