Electrodes For Potassium-ion Batteries Research Articles

Building ultra-stable K–Te battery by molecular regulation

Tellurium (Te) is an ideal electrode for potassium ion batteries (PIBs) owing to its excellent electronic conductivity and high volumetric capacity. However, the Te electrode is prone to capacity fading as the shuttle effect. To address this challenge, we propose molecular regulated Se–Te solid solutions on N-doped porous carbon as the PIBs electrode. After optimizing the Se content in Se–Te solid solutions, the resultant SeTe6.8 on N-doped porous carbon (SeTe6.8@C) delivered a capacity of over 400 mAh g−1 with a flat plateau of 1.0 V at 500 mA g−1. It also achieved a superiorly long cycle life, running for more than 1600 cycles (over 7 months with 0.015% degeneration per cycle) at 100 mA g−1 and excellent rate performance (179.9 mAh g−1 at 10000 mA g−1). This remarkable electrochemical energy storage of the Te electorde likely arises from suppression of the shuttle effect after doping the Te with strongly electronegative Se atoms (forming K5Te3 which is not easily soluble in electrolyte). This study presents a fresh approach for designing and developing ultra-stable Te-based electrodes for PIBs and beyond.

Facile synthesis of Cu2S nanoplates as anode for potassium ion batteries

Nanoplate-structured Cu2S which was anchored on carbon was synthesized by simple method and used as anode material for potassium ion batteries for the first time. As the result, the Cu2S electrode delivers a good specific capacity of 206.6 mA h g−1 at 2000 mA g−1 after 400 cycles. This work deeply influences the exploitation of electrode for potassium ion batteries, thereby promoting the development of high-performance potassium ion batteries.

Cobalt(II) dicarboxylate-based metal-organic framework for long-cycling and high-rate potassium-ion battery anode

Metal-organic frameworks (MOFs) are promising electrical storage materials due to their abundant electroactive components and large ion diffusion tunnels, however, there is no report on the employment of MOFs as electrodes for potassium-ion batteries (PIBs) hitherto. Here in this work, we firstly develop a cobalt(II) terephthalate-based layered MOF (referred as ‘L-Co2(OH)2BDC’, BDC=1,4-benzenedicarboxylate) as an anode material for PIBs. The exceptional potassium storage performance of L-Co2(OH)2BDC is demonstrated with a high reversible capacity of 188mAhg−1 after 600 prolonged cycles at 1Ag−1, revealing the considerable foreground of MOFs as superior potassium storage anodes. Moreover, the redox chemistry investigation of L-Co2(OH)2BDC based on X-ray absorption near edge structure (XANES) and soft X-ray spectroscopy (sXAS) techniques substantiate that both Co centers and organic ligands participate in the potassium storage, and the coordination between oxygen ions and cobalt significantly ensures the reversibility of potassiation and depotassiation processes. This work represents a significant step forward for the intensive application of MOFs in rechargeable metal batteries.