(1. 昆明理工大學(xué) 冶金與能源工程學(xué)院，昆明 650093；
2. 昆明理工大學(xué) 鋰離子電池與材料制備技術(shù)國家地方聯(lián)合工程實驗室，昆明 650093；
3. 云南馳宏國際鍺業(yè)有限公司，曲靖 655011)
摘 要: 過渡金屬草酸鹽基于其高比容量、優(yōu)異的倍率性能、簡單的制備工藝和豐富的資源等優(yōu)勢，在高能量鋰離子電池儲能領(lǐng)域擁有巨大的應(yīng)用潛力。然而由于其較低的電子電導(dǎo)率和Li+遷移速率，在循環(huán)過程中會形成大量電化學(xué)反應(yīng)活性較低的金屬納米粒子和聚合物，引起更高的不可逆容量，并且不穩(wěn)定的層狀結(jié)構(gòu)會造成顆粒的破裂，導(dǎo)致電池的循環(huán)壽命較差。此外，過渡金屬草酸鹽特殊的熱力學(xué)特性，導(dǎo)致獲得100%失結(jié)晶水材料更加困難。本文綜述了過渡金屬草酸鹽材料的晶體結(jié)構(gòu)特征，基于對儲鋰過程中材料轉(zhuǎn)換過程的理解和界面特性等機(jī)理研究并結(jié)合材料面臨的主要挑戰(zhàn)，深入分析了近年來在形貌微納結(jié)構(gòu)調(diào)控和增強(qiáng)產(chǎn)物反應(yīng)活性等方面的改性策略及其作用機(jī)理，為推動高能量密度過渡金屬草酸鹽基負(fù)極材料在鋰離子電池方面的基礎(chǔ)科學(xué)研究和商業(yè)化應(yīng)用提供借鑒參考。
關(guān)鍵字: 過渡金屬草酸鹽；儲能機(jī)制；轉(zhuǎn)換反應(yīng)；微納結(jié)構(gòu)調(diào)控；鋰離子電池；研究進(jìn)展
（1. Faculty of Metallurgy and Energy Engineering, Kunming University of Science and Technology, Kunming 650093, China;
2. National Local Joint Engineering Laboratory of Lithium Ion Battery and Material Preparation Technology, Kunming University of Science and Technology, Kunming 650093, China;
3. Yunnan Chihong International Germanium Industry Co., Ltd., Qujing 655011, China）
Abstract:Transition metal oxalates (TMOxs) exhibit great application potential as anode materials for high-energy density in lithium ion batteries, because of their higher electrochemical capacity, more excellent rate performance, and environmental friendliness. However, the lower electronic conductivity and slower migration of Li+ cause the formation of plenty of electrochemical production (metal nanoparticles and oxalate matrix) with reaction activity during the initial cycles, which creates larger irreversible capacity. In addition, a certain degree of disorder for their three-dimensional (3D) multi-layered structure can result in the collapse and crack around the edge of layer in micro- or nano-particles and shorten the cycling life of electrode materials. Furthermore, because of the similar temperatures for decomposition and losing crystalline water, the complete utilization of TMOxs is also challenged by the difficulty to obtain 100% free water material through dehydration. This paper detailedly reviews various crystal structures of TMOxs. Based on the understanding of confronting challenges and energy storage mechanism for TMOxs, such as the conversion reaction and interface characteristics during cycling, the modified strategies, especially in controlling of morphologies and micro-nano structure and elevating the electrochemical reactive activation for outcoming, are deeply analyzed. This paper also provides wide reference for promoting the fundamental researching and commercial application of high-energy TMOxs as anode materials in lithium-ion batteries.
Key words: transition metal oxalate; energy storage mechanism; conversion reaction; micro-nano structure regulation; lithium ion batteries; research progress
