基于资源和价格的优势，钠离子电池是比锂离子电池更具商业化潜力的大规模储能电化学器件。碳材料是最有希望商业化的钠离子电池负极材料，其优异的储钠性能来自于容量和首次库伦效率的平衡，即提升电极的表面活性，抑制电极与电解液之间的界面活性。表面活性是指碳表面有效储存钠的能力，具有活性的表面积越大，储钠位点越多，可以提供的容量越高；但同时也要抑制电解液和电极之间的界面活性，即抑制电解液在电极表面的分解，减少不可逆容量，提升首次库仑效率。在大多数无定形碳中，界面活性和表面活性是难以区分的，即无法精确的提升可逆容量，在保证容量的前提下提升首次库仑效率。缺少高首效和长平台容量的碳负极材料依然是钠离子电池产业化的主要瓶颈之一，同时钠在碳材料中的储存机理在学术界尚未达到统一。针对上述问题，本论文从以下几个方面开展研究并取得了一系列创新性成果：（1）首次揭示了商用化碳分子筛具有优异的储钠性能。通过对比多种商用化碳材料的结构和储钠性能，发现未经优化的商用碳分子筛作为钠离子电池负极可达到70%以上的首次库仑效率和300mAh g-1的容量，这样一种已经商业化的碳材料将有助于促进钠离子电池的产业化。（2）首次提出“筛分孔碳”的概念，筛分孔碳应具有两个基本的特性：一是亲钠的表面，以提升表面活性，确保容量。另一个为具有筛分作用的孔口，确保只有去溶剂化钠才能进入孔内部，从而减少了电解液在内表面的分解，抑制界面活性，提升首次库仑效率。（3）通过惰性气氛热处理（1500℃）优化的碳分子筛是很好的筛分孔碳的模型，作为钠离子电池负极材料，其首次库仑效率可达90%以上，在100mA g-1的电流密度下可逆容量密度超过300mAh g-1.（4）针对钠在碳材料中的存储特点，将从锂离子电池中借鉴的插层、吸附和孔填充三种储能形式优化为更适合钠离子电池体系的缺陷辅助的插层、缺陷主导的吸附和缺陷控制的孔填充，并基于此提出缺陷主导的储钠机理，即在斜坡区域以缺陷主导的吸附行为为主要的储钠形式，在平台区域为与缺陷相关的插层和孔填充为主要的储钠形式。从广义上讲，石墨是锂/钾离子电池的一种筛分孔碳。其表面是亲锂/钾的，层间距起到物理筛分的作用。而热处理后的碳分子筛是钠离子电池的一种筛分孔碳，其高缺陷密度的孔壁提高了储钠的表面活性，同时由于孔口物理尺寸的筛分作用，使得孔内表面只能接触到去溶剂化的钠，保证表面活性的同时抑制了界面活性，从而在提升容量的同时提升了首次库伦

Sodium-ion batteries (SIBs) are large-scale energy storage electrochemical devices with more commercial potential than lithium-ion batteries (LIBs) due to the advantages of resources and cost. Carbon materials are the most promising candidate for SIBs anode materials. Its excellent sodium storage performance comes from the balance of capacity and initial Coulomb efficiency (ICE), that is, to enhance the surface activity of electrode as well as inhibit its interface activity. Surface activity refers to the properties to store sodium and provide the active sites on the carbon surface. The interface activity refers to the electrolyte deposition on the carbon surface. The surface activity and interface activity are closely related in most amorphous carbons, which makes it challenging to ensure an enhancement of the reversible capacity. The low-cost carbon materials with sufficient cell voltage and high ICE are urgently needed to allow SIBs technology to reach the market, and the storage mechanism of sodium in carbon anodes is still controversial in academia.Given the above problems, the main perspectives and related achievements are summarized as follows: (1) We revealed for the first time that unoptimized commercial carbon molecular sieves (CMSs) have excellent sodium storage properties. By comparing the structure and sodium storage performance of various commercialized carbon materials, it was found that CMSs as SIBs anodes can achieve the ICE of more than 70% and a capacity of 300mAh g-1. Such commercialized carbon material will promote the industrialization of SIB.(2) We first proposed the concept of sieving-pore carbon, which has two essential characteristics. One is a sodiophilic surface, which ensures the surface activity and improves the capacity; the other is pore opening size with sieving effects, which show the possibility of inhibiting the surface activity and enhancement of the ICE. (3) Commercial carbon molecular sieve (CMS) pyrolyzed at 1500 ℃ is an example of sieving-pore carbon, which fails to absorb CO2 due to the size of the ultra-small pore and has defective carbon walls. It delivers an ICE of above 90% and a reversible capacity higher than 300 mAh g-1 with an extended plateau capacity.(4) Given the sodium storage characteristics in carbon materials, the intercalation, adsorption, and pore-filling mechanism are reasonable to be defect-assisted intercalation, defect-led adsorption, and defect-controlled pore-filling. Furthermore, a defect-driven sodium storage mechanism is proposed, that is, the defect-led adsorption behavior is the main form of sodium storage in the slope region, and the defect-related intercalation and pore-filling are the main in the plateau region.In this term, graphite is also a kind of sieving-pore carbon for LIB and KIB, as the d-spacing between layers is a particular slit pore and its surface is lithophilic and potaophilic. Graphite can not be a sieving-pore carbon for sodium as its surface is not sodiophilic. The CMS is a kind of sieving-pore carbon for SIBs. Its high defect density pore wall improves the surface activity. At the same time, due to the sieve effect of the pore opening, the inner surface of the pore can only be exposed to desolvated sodium, ensures surface activity while suppressing interfacial activity, thereby increasing the capacity and the ICE.