Nickel-Salen Type Polymers as Cathode Materials for Rechargeable Lithium Batteries

The nickel salen‐type redox polymers represent an interesting class of organometallic polymers frequently used in hybrid supercapacitor electrodes as thin films and carbon material composites. However, the suitability of these compounds for application as electrode materials for rechargeable batteries has not yet been tested. In this study, redox processes in monocomponent electrodes based on a series of nickel salen‐type redox polymers are investigated in 1mLiPF₆in 1:1 ethylene carbonate (EC)/diethyl carbonate (DEC) electrolyte in a Li‐ion battery. The oxidation potentials for polymer complexes of nickel exceed 3.5 V versus Li/Li⁺, which enhances specific energy. It is found that introduction of a proper substituent in the phenyl ring of the ligand allows to fabricate additive‐free electrodes which demonstrate high charge/discharge rate performance with the capacity on discharge at 10Cbeing up to 73% of the capacity obtained at discharge at 1C, which corresponds to maximum power of 2.6 kW kg⁻¹.