Prelithiated, Multiscale Nickel Phosphate Octahydrate Platelets by a Tailored Nanoarchitectonics Approach

Abstract

Nickel phosphate octahydrate (Ni 3 (PO 4 ) 2 •8H 2 O) is a promising electrode material for next-generation energy storage devices. However, owing to the large initial irreversible capacity, its practical application is hindered. Prelithiation is a viable solution, nonetheless, usually associated with additional challenges in terms of safety, cost, and homogenous distribution of Li + . Herein, we report on a facile, cost-effective prelithiation method based on nanoarchitectonics for the synthesis of mesocrystalline Ni 3 (PO 4 ) 2 • 8H 2 O platelets. During their oriented self-assembly, the lithium phosphates present in the precursor act as the Li + source. A detailed, systematic investigation of the morphological evolution, from activation over nucleation to growth, revealed that the addition of a secondary phase with oxygen-containing functional groups accelerates the fabrication of complex multiscale hybrid materials. Accordingly, hybridization with graphene oxide (GO), cellulose nanofibers (CNF), and V 2 O 5 nanofibers (VNF) was demonstrated. The electrochemical assessment of the prelithiated multiscale material in the form of a free-standing aerogel revealed the benefits of the synergy of nanoarchitecture and prelithiation. Specifically, it decreases the effect of the initial capacity loss, facilitates ion intercalation, and introduces additional intercalation sites. Notably, dehydrated aerogels of the prelithiated nickel phosphate embedded in partially reduced GO deliver a significantly high capacity of 400 mAh g −1 when tested as the anode. The developed prelithiation strategy provides enlightenment for novel environmentally conscious synthesis routes for the commercial application of high-specific-capacity electrodes.