Low‐strain TiP₂O₇ with three‐dimensional ion channels as long‐life and high‐rate anode material for Mg‐ion batteries

Abstract

Rechargeable magnesium batteries are identified as a promising next‐generation energy storage system, but their development is hindered by the anode−electrolyte−cathode incompatibilities and passivation of magnesium metal anode. To avoid or alleviate these problems, the exploitation of alternative anode materials is a promising choice. Herein, we present titanium pyrophosphate (TiP2O7) as anode materials for magnesium‐ion batteries (MIBs) and investigate the effect of the crystal phase on its magnesium storage performance. Compared with the metastable layered TiP2O7, the thermodynamically stable cubic TiP2O7 displays a better rate capability of 72 mAh g−1 at 5000 mA g−1. Moreover, cubic TiP2O7 exhibits excellent cycling stability with the capacity of 60 mAh g−1 after 5000 cycles at 1000 mA g−1, which are better than previously reported Ti‐based anode materials for MIBs. In situ X‐ray diffraction technology confirms the single‐phase magnesium‐ion intercalation/deintercalation reaction mechanism of cubic TiP2O7 with a low volume change of 3.2%. In addition, the density functional theory calculation results demonstrate that three‐dimensional magnesium‐ion diffusion can be allowed in cubic TiP2O7 with a low migration energy barrier of 0.62 eV. Our work demonstrates the promise of TiP2O7 as high‐rate and long‐life anode materials for MIBs and may pave the way for further development of MIBs.

NaSICON: A promising solid electrolyte for solid‐state sodium batteries

“…Driven by the ever-increasing global concerns that arise from the use of fossil fuels, tremendous efforts have been devoted to the development of clean and efficient energy conversion and storage technologies. [1][2][3][4][5] Owing to their high energy and power densities, lithium-ion batteries have been the energy storage system of choice for many devices spanning from portable electronics to electric vehicles. [6][7][8] However, the rising lithium costs and limited resources may limit their application in the field of large-scale energy storage systems in near future.…”

Incorporating Near‐Pseudocapacitance Insertion Ni/Co‐Based Hexacyanoferrate and Low‐Cost Metallic Zn for Aqueous K‐Ion Batteries

“…[7] Notably, the large frame structure of PBAs could buffer the microstructural strain during the ion intercalation process, which is beneficial to improve structural stability and produce a significantly longer cycle life. [8] The chemical formula of PBAs is defined as A x M 1 [M 2 (CN) 6 ] y • nH 2 O (0 � x � 2; y � 1), where A indicates alkali metal ions, such as Li + , Na + , and K + ; M 1 and M 2 represent transition metal elements, such as Ni, Cu, Fe, Mn, and Co. Moreover, a large channel size can allow reversible intercalation of K + from three dimensions.…”

“…Thus, PBAs are convenient for large‐radius ion transmission as they ensure rapid ionic conduction for a high‐rate capability [7] . Notably, the large frame structure of PBAs could buffer the microstructural strain during the ion intercalation process, which is beneficial to improve structural stability and produce a significantly longer cycle life [8] . The chemical formula of PBAs is defined as A x M 1 [M 2 (CN) 6 ] y ⋅ nH 2 O (0 ≤ x ≤2; y ≤1), where A indicates alkali metal ions, such as Li + , Na + , and K + ; M 1 and M 2 represent transition metal elements, such as Ni, Cu, Fe, Mn, and Co.…”

Challenges and Perspectives for Doping Strategy for Manganese-Based Zinc-ion Battery Cathode

“…Among those energy storage devices, aqueous electrolytes have been widely employed in secondary battery systems for Na + , K + , Mg 2+ , Al 3+ , Ca 2+ , Zn 2+ , etc. in recent years because of their safety, high ionic conductivity, and ease of operation [15,16]. Among aqueous multivalent ion batteries, ZIBs stand out due to the following characteristics: (1) Zn metal reserves are abundant and the manufacture process of ZIBs occurs in an air environment, making it cost-effective; (2) Zn metal anode has a low redox potential of −0.76 V with respect to a standard hydrogen electrode and high theoretical gravimetric/volumetric capacity (820 mAh•g −1 /5855 mAh•cm −3 ); (3) Zn metal can be directly applied as an anode due to its excellent electrochemical stability and reversibility in water; (4) ZIBs are highly safe because of the application of nontoxic aqueous electrolyte [17,18].…”