Lithium and potassium storage behavior comparison for porous nanoflaked Co3O4 anode in lithium-ion and potassium-ion batteries

Abstract Rising cost has generated extended interest from lithium-ion (LIBs) to potassium-ion batteries (PIBs). Here, attempts are concentrated on comparative study on electrochemical Li and K storage behavior features for porous nanoflaked (PNF) Co3O4 anode in LIBs and PIBs. PNF–Co3O4 is synthesized by a facile solution-combustion route and its growth-mechanism is proposed as “bubble-gum fracturing effect”. Such PNF–Co3O4 presents both encouraging Li and K storage reactivity. But considering larger-sized K+, it presents a slightly lower reversible capacity (417 mAh g−1) and obviously higher charge-transfer-resistance (516.8 Ω) in PIBs than LIBs (743.9 mAh g−1, 46.0 Ω), implying moderate K+ electrode-kinetics. However, this capacity in PIBs is better than most explored carbon/alloy-based PIBs-anodes. Additionally, first, the substantially lower (nearly 1 V difference) discharge-plateau in PIBs than LIBs indicates a higher operating-voltage full-cell for PIBs than LIBs; Second, this discharge-plateau (0.3 V vs. K+/K) in PIBs slightly higher than potassium-plating-potential could potentially alleviate partial dendrite-formation. Also, enhanced performance for PNF–Co3O4 compared with bulk-Co3O4 confirms marked benefits of PNF-structure in both LIBs and PIBs on shortening Li+/K+ diffusion-distance and enduring volume-swelling. These findings demonstrate extended advantages from LIBs to PIBs for nanostructured Co3O4 and offer a better understanding of its Li and K storage behavior.