Anode-Free Lithium Metal Batteries Based On Lithium-Rich Manganese-Based Cathodes

Since the commercialization of lithium-ion batteries,the application of batteries has become more and more extensive,from miniaturized electronic products to grid storage,especially with the advancement of"carbon neutrality",the demand for high-energy density batteries has become increasingly urgent.Lithium metal has the lowest oxidation-reduction potential-3.04 V（vs Standard hydrogen electrode）and high theoretical capacity(3860 m Ah g^-1,2061 m Ah cm^-3),and is considered to be the next-generation ideal anode material.Compared with the traditional graphite anode(372 m Ah g^-1),it can better realize the high energy density of the battery.However,in general,too much lithium will be used in the lithium metal anodes,and the undesirable side reactions caused by the poor deposition of metal lithium consume too much lithium metal,which weakens the advantagement of energy density brought by the lithium metal anodes.The new battery structure——the anode-free lithium metal batteries can greatly increase the energy density of the battery by removing the anode part.However,the anode-free lithium metal batteries have a limited lithium inventory due to the lack of excess lithium metal supplement in the anode electrode,and the high reactivity of metal lithium leads to a rapid capacity loss and poor coulombic efficiency and cycling lifespan issue of the anode-free lithium metal batteries.Aiming at the problems of anode-free lithium metal batteries,this article synthesized high-voltage lithium-rich manganese-based material Li_1.18Mn_0.52Co_0.15Ni_0.15O₂and use it as the cathode of anode-free lithium metal batteries to achieve a better performance than commercial cathode material NCM523,meanwhile has a higher voltage,which increases the energy density of the battery.In this work,by comparing the charge and discharge performence of the them in the first cycle of the half-cell and the effect of deposition on the anode current collector,it is proved that the lithium-rich materials have the characteristics of large irreversible capacity in the first cycle,which can be used to supple lithium of anode-free lithium metal batteries,and provide a feasible way to solve the problem of insufficient lithium inventory in anode-free lithium metal batteries.In order to further solve the problems of high reactivity of metal lithium and carbonate electrolytes and poor deposition of lithium,this article explores the use of PVDF-HFP and Li F composite membranes to optimize the anode.In this way,an artificial protective layer is built on the anode to maintain a good interface during the cycles,and it can limit the growth of lithium dendrites,and reduces the reaction consumption of metal lithium and electrolyte,thereby further improving the cycle life of the anode-free lithium metal batteries.