Stacking Ni-Al and Co-Al Layered Double Hydroxide for High-Energy and High-Power Composite Electrodes

The requirement for high-power performance of secondary batteries suffering from inherent sluggish charge transfer kinetics is urgent for the expanding energy storage and conversion applications such as electric vehicles. A successful combination of high-power supercapacitors with high-energy secondary batteries in one energy storage device will meet the needs of both high power and energy density. We study the electrochemical behaviors of alternately stacked super-capacitive [Co4Al(OH)(10)]NO3 and [Ni4Al(OH)(10)]NO3 layered double hydroxide (LDH) electrodes. By cyclic voltammetry studies, the sandwich of [Co4Al(OH)(10)]NO3 lDH between [Ni4Al(OH)(10)]NO3 LDH and the Pt current collector results in the current amplification of the oxidation or reduction peaks to 4-35 times. By galvanostatic charging/discharging, the 3-stacked Ni-Al|Co-Al|Ni-Al LDH electrode behaves better than the Co-Al|Ni-Al|Co-Al LDH electrode, exhibiting a maximal capacity, 338.1 mAh.g(-1) under a current density of 1000 mA.g(-1) and maintaining 288.6 mAh.g(-1) within 400 cycles. It also has a much lower liquid-solid interface capacitor resistance and lower self-discharge. These results suggest that stacking in a suitable sequence contributes to high electrode performances, providing a strategy for producing energy storage and conversion devices. A synergetic charge transfer for the combination of Ni-Al and Co-Al LDH suggests that Co-Al LDH outstands as a bridge, accelerating the transfer of electrons.(C) 2023 The Electrochemical Society ("ECS"). Published on behalf of ECS by IOP Publishing Limited.