Manipulation of an ionic and electronic conductive interface for highly-stable high-voltage cathodes

Highlights: • A controllable Li₃PO4–TiO₂ (LPO-TiO) hybrid interface material is employed for LNMO. • Hybrid LPO-TiO suppresses the polarization as well as facilitates Li-ion migration. • Modified cathode shows excellent cycling stability with improved rate capability. • LPO-TiO suppresses dissolution of Mn and maintains the integral structure of LNMO. -- Abstract: A stable and conductive interface is one of the decisive factors in manipulating the performance of high voltage LiNi_0.5Mn_1.5O₄ (LNMO) cathode for Li-ion batteries. Herein, a hybrid Li₃PO₄–TiO₂ coating layer is designed as an interfacial material via controllable atomic layer deposition (ALD) on LNMO. The coating acts not just as a physical barrier to prevent the side-reactions between cathode and electrolyte at high voltage, more importantly, the hybrid coating material improves both interfacial ionic and electronic conductivities to build facile Li-ion and electron diffusion pathways for LNMO. The optimized LNMO demonstrates improved rate capability and long-life stability. The capacity retention is 81.2% comparing with 47.4% of bare LNMO at 0.5C after 300 cycles. Detailed surface structural evolution is studied via X-ray absorption near edge spectroscopy and transmission electron microscopy. This work provides new insights of hybrid interfacial design via ALD and promotes novel electrode architectures for batteries.