Hydrogen-bonded organic framework modified separator for simultaneously enhancing the safety and electrochemical performance of Ni-rich lithium-ion battery

Nickel-rich layered oxide cathode (LiNi x Co y Mn 1− x − y O 2 , x  > 0.5, NCM) shows substantial potential for applications in longer-range electrical vehicles. However, the rapid capacity decay and serious safety concerns impede its practical viability. This work provides a hydrogen-bonded organic framework (HOF) modification strategy to simultaneously improve the electrochemical performance, thermal stability and incombustibility of separator. Melamine cyanurate (MCA), as a low-cost and reliable flame-retardant HOF, was implemented in the separator modification layer, which can prevent the battery short circuit even at a high temperature. In addition, the supermolecule properties of MCA provide unique physical and chemical microenvironment for regulating ion-transport behavior in electrolyte. The MCA coating layer enabled the nickel-rich layered oxide cathode with a high-capacity retention of 90.3% after 300 cycles at 1.0 C. Collectively, the usage of MCA in lithium-ion batteries (LIBs) affords a simple, low-cost and efficient strategy to improve the security and service life of nickel-rich layered cathodes.