Amorphization-Driven Lithium Ion Storage Mechanism Change for Anomalous Capacity Enhancement

Abstract

Capacity fading as a function of lithiation/ delithiation cycles is a major limitation of Li-ion batteries. Most Li storage materials are susceptible to this phenomenon due to the degradation of the crystal structure and particle integrity as a result of volume changes associated with lithiation/delithiation processes and/or irreversible redox reactions. However, some Li storage materials show an increase in capacity with an increase in cycles; this phenomenon has been termed "negative fading." Negative fading in Li host materials is usually associated with the additional charge storage at the particle/solid−electrolyte interface (SEI) layer, decomposition/formation of the SEI layer, or redox reactions of various Li species at the interface. In this work, we report the observation of negative fading in a newly discovered anode material, TiNbO 4 (TNO), and reveal amorphization as a new mechanism for negative fading in Li host materials. This assertion was confirmed via a close relationship between changes in the crystal structure and the Li storage mechanism in TNO. Given that other titanium niobium oxide analogues (e.g., TiNb 2 O 7 ) suffer from capacity loss due to amorphization, this unique electrochemical behavior of TNO may provide an interesting new direction to tune the titanium niobium oxides for high-performance, stable battery anodes.

Core‐Shell Architectured Sulfur Coated α‐Fe2O3 Nano‐Sheet Anode for Li‐Ion Battery with Insitu Active Solid Electrolyte Interfacial Layer and Li‐Sulfur Energy Storage Systems

“…Lithium-ion batteries (LIBs) are an indispensable part of modern society that offer electrical energy for multiple applications such as eco-friendly Electrical Vehicles (EVs), electrical flight, and portable Electronic Devices (EDs) in the electronics market. [1,2] Though the lithium-ion battery field achieved technical maturity, a few unresolved issues limit the capacity and energy density yield in the industrial market. Negative electrodes are the key materials to achieve high capacity; however, extracting capacity equivalent to theoretical values of any anode material is a challenging task.…”