Activation-Assisted High-Concentration Phosphorus-Doping to Enhance the Electrochemical Performance of Cobalt Carbonate Hydroxide Hydrate

Activation-assisted P-doping strategywas explored to raisethe P-doping concentration and improve the electrochemical performanceof cobalt carbonate hydroxide hydrate. P-doping into metal oxides has been demonstrated as avalid avenueto ameliorate electrochemical performance because it can tune theelectronic structures and increase the active sites for an electrochemicalreaction. However, it usually results in a low P-doping concentrationvia the commonly used gas phosphorization method. In this work, anactivation-assisted P-doping strategy was explored to significantlyraise the P-doping concentration in cobalt carbonate hydroxide hydrate(CCHH). The activation treatment increased active sites for electrochemicalreaction and endowed the sample with a high P content in the subsequentgas phosphorization process, thereby greatly enhancing the conductivityof the sample. Therefore, the final CCHH-A-P electrode exhibited ahigh capacitance of 6.62 F cm(-2) at 5 mA cm(-2) and good cyclic stability. In addition, the CCHH-A-P//CC ASC withCCHH-A-P as the positive electrode and carbon cloth as the negativeelectrode provided a high energy density of 0.25 mWh cm(-2) at 4 mW cm(-2) as well as excellent cycling performancewith capacitance retention of 91.2% after 20,000 cycles. Our workshows an effective strategy to acquire Co-based materials with high-concentrationP-doping that holds great potential in boosting the electrochemicalperformance of electrode materials via P-doping technology.