Recent advances in zinc-ion hybrid energy storage: Coloring high-power capacitors with battery-level energy

Non-Metal Ion Storage in Zinc-Organic Batteries

Zinc-organic batteries (ZOBs) are receiving widespread attention as up-and-coming energy-storage systems due to their sustainability, operational safety and low cost. Charge carrier is one of the critical factors affecting the redox kinetics and electrochemical performances of ZOBs. Compared with conventional large-sized and sluggish Zn2+ storage, non-metallic charge carriers with small hydrated size and light weight show accelerated interfacial dehydration and fast reaction kinetics, enabling superior electrochemical metrics for ZOBs. Thus, it is valuable and ongoing works to build better ZOBs with non-metallic ion storage. In this review, versatile non-metallic cationic (H+, NH4 +) and anionic (Cl-, OH-, CF3SO3 -, SO4 2-) charge carriers of ZOBs are first categorized with a brief comparison of their respective physicochemical properties and chemical interactions with redox-active organic materials. Furthermore, this work highlights the implementation effectiveness of non-metallic ions in ZOBs, giving insights into the impact of ion types on the metrics (capacity, rate capability, operation voltage, and cycle life) of organic cathodes. Finally, the challenges and perspectives of non-metal-ion-based ZOBs are outlined to guild the future development of next-generation energy communities.

Status and Opportunities of Zinc Ion Hybrid Capacitors: Focus on Carbon Materials, Current Collectors, and Separators

Zinc ion hybrid capacitors (ZIHCs), which integrate the features of the high power of supercapacitors and the high energy of zinc ion batteries, are promising competitors in future electrochemical energy storage applications. Carbon-based materials are deemed the competitive candidates for cathodes of ZIHC due to their cost-effectiveness, high electronic conductivity, chemical inertness, controllable surface states, and tunable pore architectures. In recent years, great research efforts have been devoted to further improving the energy density and cycling stability of ZIHCs. Reasonable modification and optimization of carbon-based materials offer a remedy for these challenges. In this review, the structural design, and electrochemical properties of carbon-based cathode materials with different dimensions, as well as the selection of compatible, robust current collectors and separators for ZIHCs are discussed. The challenges and prospects of ZIHCs are showcased to guide the innovative development of carbon-based cathode materials and the development of novel ZIHCs.

Boosting capacitive performance of N, S co-doped hierarchical porous lignin-derived carbon via self-assembly assisted template-coupled activation

Heteroatom-doped porous carbon materials show promise for use as supercapacitor electrodes, but the tradeoff between surface area and the heteroatom dopant levels limits the supercapacitive performance. Here, we modulated the pore structure and surface dopants of N, S co-doped hierarchical porous lignin-derived carbon (NS-HPLC-K) via self-assembly assisted template-coupled activation. The ingenious assembly of lignin micelles and sulfomethylated melamine into a magnesium carbonate basic template greatly promoted the KOH activation process, which endowed the NS-HPLC-K with uniform distributions of activated N/S dopants and highly accessible nanosized pores. The optimized NS-HPLC-K exhibited a three-dimensional hierarchically porous architecture composed of wrinkled nanosheets and a high specific surface area of 2538.3 ± 9.5 m²/g with a rational N content of 3.19 ± 0.01 at.%, which boosted the electrical double-layer capacitance and pseudocapacitance. Consequently, the NS-HPLC-K supercapacitor electrode delivered a superior gravimetric capacitance of 393 F/g at 0.5 A/g. Furthermore, the assembled coin-type supercapacitor showed good energy-power characteristics and cycling stability. This work provides a novel idea for designing eco-friendly porous carbons for use in advanced supercapacitors.