Low Volume‐Expansion, Insertion‐Type Layered Silicate Hierarchical Structure For Superior Storage Of Li, Na, K

Abstract

A hierarchical structure is successfully synthesized by coating polypyrrole (PPy) on the surface of carbon/saponite superlattice (denoted as PPy@C/SAP), and applied as low volume‐expansion insertion‐type anode for Li, Na, K storage.The synergistic effect of metal Ni, Fe doping, carbon/silicate superlattice, abundant oxygen vacancies and PPy coating leads to a good electronic conductivity and large current discharging capability. As a Si‐based material, PPy@C/SAP has excellent storage capability for Li (659 mAh g−1 after 1000 cycles at 2 A g−1 and 550 mAh g−1 after 1000 cycles at 5 A g−1), Na (maximum specific capacity of 533 and 327 mAh g−1 after 50 cycles) as well as K (236 mAh g−1 after 100 cycles). XPS, XANES, XRD, FTIR, HRTEM, SEM are used to detect the hybrid mechanism (bulk insertion and surface conversion) with a volume expansion as low as 9%. Insertion reaction driven by valence state change of Ni, Fe, Si (Ni0⇔Ni2+, Fe0⇔Fe3+, Si2+⇔Si4+) in laminates and conversion reactions between LiOH/Li2CO3 and LiH/Li2C2 catalyzed by Ni° contribute to the high performance. In the whole electrochemical process, layered structure is retained while the conversion reactions of LiOH (prodeced by laminates dehydroxylation) and Li2CO3 (electrolyte decomposition) cause the dynamic evolution of solid ectrolyte interphase. This study develops a promising Si‐based anode material for lithium ion batteries, sodium ion batteries and potassium ion batteries, which is significant for designing long cycle life rechargeable batteries.

Design and synthesis of few-layer molybdenum oxide selenide encapsulated in a 3D interconnected nitrogen-doped carbon anode toward high-performance sodium storage

“…14 Among them, layered transition metal dichalcogenides (MX 2 , where X stands for S, Se, or Te) with two-dimensional (2D) layered structures with large and adjustable interlayer spacings have proven to be good potential SIB anodes. [15][16][17] However, the practical application of most MX 2 suffers from severe pulverization caused by volume expansion upon cycling, 18,19 leading to a significant decline of electrical conductivity and decay of capacity upon cycling.…”

Design of grid-like triple-carbon matrix confined ultrafine CoTe2 nanocrystals toward durable and fast potassium storage

“…Moreover, the subsequent PPy coating and in situ tellurization process led to the formation of a composite material with an outer carbon armor and inner grid-like carbon-encased CoTe 2 nanocrystals. 35,36 The inner carbon grid effectively suppresses the aggregation and uncontrolled growth of CoTe 2 nanocrystals during the high-temperature tellurization process, while also providing abundant nitrogen active sites for anchoring polytellurides. In addition, the outer carbon armor not only provides additional anchoring points, but also serves as a defense line to suppress volumetric stress and maintain the overall structural stability.…”

A comprehensive review of atomically thin silicates and their applications

“…2D silicates have shown improved performance in Li-ion and Na-ion batteries and redox flow batteries, thus contributing to improved battery performance in terms of capacity, cycle life, and chargedischarge rates [78]. Potassium-ion batteries, a new area of study, have potential applications in grid-scale energy storage [118]. Due to their high surface area, tunable chemistry, and potential cost-effectiveness, 2D silicates can be investigated for supercapacitor applications [119].…”