Oxygen defect-engineered Zn2P2O7−y as an anode material for lithium-ion batteries

Abstract

Zn₂P₂O_7−y (referred to as ZPO) is expected to be an ideal anode material for lithium-ion batteries (LIBs) owing to its low cost, good chemical and thermal stability, and environmental friendliness. The effects of oxygen vacancies on the structure, morphology, and electrochemical performance of ZPO were systematically investigated. The sample obtained in an argon–hydrogen atmosphere (referred to as ZPO-1) exhibited an initial discharge capacity of 1178.4 mA h g⁻¹ at 0.2 A g⁻¹, which was superior to that of the samples obtained via calcination in argon (referred to as ZPO-2, 749.1 mA h g⁻¹), vacuum (referred to as ZPO-3, 901.3 mA h g⁻¹), and the air (referred to as ZPO-4, 911.2 mA h g ⁻¹). The excellent electrochemical performance of ZPO-1 could be attributed to the introduction of more defects under reducing atmospheres, which accelerated the transmission rate of lithium ions and improved discharge capacity. Appropriate amounts of oxygen vacancies not only enhance electrical conductivity, but also act as active sites for electrochemical reactions. Additionally, synthesizing ZPO with oxygen vacancies provides a reference for exploring anode materials with exceptional performances for LIBs.