鋰離子電池高比容量NCA正極材料研究
發(fā)布時間：2019-01-24 12:06
【摘要】：為了實現(xiàn)綠色能源持續(xù)穩(wěn)定的供應(yīng),研究和開發(fā)能量存儲器件(如鋰離子電池)的速度需要進(jìn)一步加快。層狀結(jié)構(gòu)的LiNi_(0.8)Co_(0.15)Al_(0.05)O_2 (NCA)正極材料,因其高容量的優(yōu)勢,成為高能量密度鋰離子電池中的正極材料之一。本論文針對NCA材料,采用優(yōu)化碳酸鹽共沉淀的合成方法,通過AlPO4包覆NCA來提升性能,并設(shè)計及合成了一種梯度材料,并對它的性能進(jìn)行研究。主要內(nèi)容包括:1、碳酸鹽共沉淀法合成NCA材料以LiNi_(0.8)Co_(0.15)Al_(0.05)O_2 (NCA)為例,優(yōu)化了合成條件,采取的反應(yīng)溫度為60℃,pH值為8.10,進(jìn)料速度為500mL h-1,以一定的速度進(jìn)行攪拌約1h后取出沉淀,進(jìn)行過濾,洗滌和干燥,即得到大小均勻的NCA前驅(qū)體球形顆粒。然后與氫氧化鋰以1:1.05的比例進(jìn)行研磨混勻,在空氣中高溫鍛燒一定時間,得到具有較好的層狀結(jié)構(gòu)以及良好電化學(xué)性能的NCA材料。2、AlP0_4包覆NCA材料制備及性能研究利用濕化學(xué)法在NCA表面均勻包覆了一層AlP0_4,目的是防止NCA與電解液接觸時發(fā)生的副反應(yīng)。NCA@AlPO4材料在充放電過程中具有較高的容量,同時具有優(yōu)異的循環(huán)性能。在3.0-4.3 V的電壓區(qū)間,0.5 C的倍率下循環(huán)150圈后,AlPO4包覆NCA材料的容量保持率為86.9%,高于未包覆的NCA(66.8%)。此外,由于NCA表面包覆層的作用,材料的熱穩(wěn)定性也得到極大提升。結(jié)果表明,AlP0_4包覆的NCA材料可以作為鋰離子電池中具有高安全性和高容量的正極材料之一。3、梯度結(jié)構(gòu)鋰離子電池正極材料的制備與性能研究通過碳酸鹽共沉淀法合成了濃度梯度的球形顆粒材料,該材料組成從內(nèi)層的LiNi_(0.8)Co_(0.15)Al_(0.05)O_2 (NCA)逐漸渡至外層的LiNi1/3Co1/3Mn1/3O2(NCM)。0.5 C的倍率下循環(huán)200圈后仍有99.8%的容量保持率,表現(xiàn)出優(yōu)異的循環(huán)性能。這得益于NCM濃度梯度保護(hù)層對于內(nèi)層NCA的保護(hù)作用。此外,材料具有更高的熱穩(wěn)定性和空氣穩(wěn)定性,可以滿足日益增長的對于高能量密度,長循環(huán)壽命和高儲能穩(wěn)定性鋰離子電池的需求。
[Abstract]:In order to achieve a sustainable and stable supply of green energy, the research and development of energy storage devices (such as lithium ion batteries) need to be further accelerated. Layered LiNi_ (0. 8) Co_ (0. 15) Al_ (0. 05) O\ -2 (NCA) cathode materials have become one of the cathode materials in high energy density lithium ion batteries due to their high capacity. In this paper, a kind of gradient material was designed and synthesized by optimizing the synthesis method of carbonate coprecipitation and AlPO4 coating NCA to improve the properties of NCA materials, and its properties were studied. The main contents are as follows: 1. The synthesis conditions of NCA materials synthesized by carbonate coprecipitation were optimized with LiNi_ (0.8) Co_ (0.15) Al_ (0. 05) O _ 2 (NCA) as an example, and the reaction temperature was 60 鈩，
本文編號：2414460
[Abstract]:In order to achieve a sustainable and stable supply of green energy, the research and development of energy storage devices (such as lithium ion batteries) need to be further accelerated. Layered LiNi_ (0. 8) Co_ (0. 15) Al_ (0. 05) O\ -2 (NCA) cathode materials have become one of the cathode materials in high energy density lithium ion batteries due to their high capacity. In this paper, a kind of gradient material was designed and synthesized by optimizing the synthesis method of carbonate coprecipitation and AlPO4 coating NCA to improve the properties of NCA materials, and its properties were studied. The main contents are as follows: 1. The synthesis conditions of NCA materials synthesized by carbonate coprecipitation were optimized with LiNi_ (0.8) Co_ (0.15) Al_ (0. 05) O _ 2 (NCA) as an example, and the reaction temperature was 60 鈩，
本文編號：2414460
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