Porous ZrNb24O62 nanowires with pseudocapacitive behavior achieve high-performance lithium-ion storage

Abstract

The ever-increasing power and energy demands for modern consumer electronics and electric vehicles are driving the pursuit of energy-storage technologies beyond the current horizon. Pseudocapacitive charge storage is one of the most effective and promising approaches to fill this technology gap, owing to its potential to deliver both high power and energy densities. Typically, titanium niobium oxides (TiNb_xO_2+2.5x (x = 2, 5 and 24)) with intrinsic pseudocapacitance, high safety and theoretical capacities of 388–402 mA h g⁻¹ are recognized as promising anode materials for lithium-ion batteries. However, their poor conductivity and low Li⁺-ion diffusion coefficient are known to be the major hurdles limiting the full utilization of their pseudocapacitive effects, leading to their lackluster rate capabilities. Herein, we employ a facile electrospinning method to prepare one-dimensional hierarchically porous ZrNb₂₄O₆₂ nanowires (P-ZrNb₂₄O₆₂) with an ultra-large Li⁺-ion diffusion coefficient as a new intercalating pseudocapacitive material for boosting Li⁺-ion storage. The P-ZrNb₂₄O₆₂ exhibits excellent electrochemical performances, including a high reversible capacity (320 mA h g⁻¹ at 0.1C), safe working potential (∼1.67 V vs. Li/Li⁺), high initial coulombic efficiency (90.1%), outstanding rate capability (182 mA h g⁻¹ at 30C) and durable long-term cyclability (90.2% capacity retention over 1500 cycles).