【Applied Energy】还原氧化石墨烯包覆的氧化锰对氨离子电池的物理化学效应

AEii国际应用能源 · 公众号 · · 2023-11-27 12:16

正文

原文信息

Investigating the physical-chemical effects of reduced graphene oxide-covered manganese oxide on ammonium-ion batteries

原文链接：https://www.sciencedirect.com/science/article/abs/pii/S0306261923014319?via%3Dihub

Highlights

(1) 还原氧化石墨烯覆盖在MnO _x 表面提高了MnO _x 基铵离子电池的性能

(2) 还原氧化石墨烯作为阻隔层可抑制Mn ²⁺ 和NO _x ^- 离子向电解液中扩散

(3) 研究了还原氧化石墨烯对电解液中NH ₄ ⁺ 离子的电化学行为的影响

Research gap

正极材料对水系铵离子电池中铵离子影响的研究一直未受到重视。本研究在提高正电极材料性能的同时，还研究了正极材料对铵离子电化学行为的影响。

摘要

水系铵离子电池逐渐受到人们的关注。电沉积氧化锰(MnO _x )电极在储存NH ₄ ⁺ 方面表现出优异的电化学性能。然而，由于MnO _x 的导电性差和自溶性，限制了其作为铵离子电池电极材料的广泛应用。在本研究工作中，通过电化学覆盖法，将还原氧化石墨烯(rGO)包覆在MnO _x 表面，以改善MnO _x 作为铵离子电池正极的性能。rGO作为导电层（快速的电子运输）、阻隔层（抑制Mn ²⁺ 和NO _x ^- 扩散）以及其电容特性（吸附Mn ²⁺ 和NO _x ^- ）使rGO ₆₀ /MnO _x 表现出优异的倍率性能（5 A g ^-1 ，109 mAh g ^-1 ）和循环稳定性能（循环1000圈，比容量保持率为92.6%）。此外，本文还研究了NH ₄ ⁺ 在还原氧化石墨烯层上的氧化还原过程，以考察电解质的稳定性。实验结果表明NH ₄ ⁺ 在还原氧化石墨烯层上的氧化还原具有高可逆性和低活性。这一研究结果表明还原氧化石墨烯适合作为改善MnO _x 性能的功能化组分。本研究为铵离子电池电极的设计提供了一种新的思路。

Abstr act

Aqueous ammonium-ion batteries have attracted more attentions. Electrodeposited manganese oxide (MnO _x ) electrodes stand out electrochemical behaviors for storing NH ₄ ⁺ . However, the unsatisfied conductivity and dissolution of MnO _x impede electrochemical properties of MnO _x for applying in ammonium-ion batteries. In this work, electrochemical coverage of reduced graphene oxide (rGO) layers on MnO _x was carried out to improve the properties of MnO _x as a positive electrode of ammonium-ion batteries. The improvements are attributed to three functions of rGO additives to engage as conductive layers (fast electron transportation), blocking layers (inhibition of Mn ²⁺ diffusion) and capacitive behaviors (adsorption of Mn ²⁺ and NO _x ^- ), which makes sure the excellent rate capability (109 mAh g ^-1 at 5 A g ^-1 ) and cycling stability (92.6% after 1000 cycles) of rGO ₆₀ /MnO _x . In addition, we also studied the redox of NH ₄ ⁺ on rGO layers to investigate the stability of electrolyte, and the redox of NH ₄ ⁺ on rGO layers is highly reversible and low active, which implies that the rGO is suitable to be a functionalized component for improving the properties of MnO _x to apply in ammonium-ion batteries. This work provides a new thought to design electrodes with comprehensive strategies for ammonium-ion batteries.