## 1 Introduction  
Being a type of electrochemical devices, solid oxide fuel cells (SOFCs) have been receiving attentions as one of the most promising power generation systems [1]. While Nickel (Ni), as an important material in electrochemical technology, is used widely as anode material in SOFCs [2; 3; 4; 5]. Typical SOFC anodes contain 40-60 wt% nickel, which imparts favorable microstructure, electrical conductivity, thermal robustness and catalytic activity to the anode [4]. In contrast to disordered porous structures, materials with high surface area and highly ordered pore network would be expected to exhibit superior performance in electrochemical systems which rely on gas or liquid diffusion within the electrode material [6]. [PERSON] et al. [6] have successfully produced highly ordered nanoporous nickel (HONN) via the liquid crystal templated electrodeposition route. Moreover, the monolithic HONNs make electron transport within the material not to encounter grain boundary resistances, offering the material superior electronic conductivity and removing power losses [7]. Since SOFCs usually operate at a range of temperature from 600 to 1000 \({}^{\circ}\)C, thermal stresses in various components of SOFCs strongly impact the cell lifetime by inducing cracks, contact loss and structural instability [8]. It is desired that the HONNs have not only enough chemical and electrochemical stability but also excellent mechanical properties to withstand stresses that arise during processing and service. On the other hand, the discovery of carbon nanotubes (CNTs) [9] stimulated enormous studies on carbon nanomechanics because of their extraordinary strength [10], high electrical properties [11] and high thermal conductivity [12]. CNTs have been used in electrode materials of various cells [13; 14; 15] and reinforcement fillers of different structural materials [16; 17; 18]. Porosity have been assumed to be an important factor that affects the mechanical properties of anode materials of SOFCs [3; 19; 20] and therefore, mechanical properties of HONNs with different porosity and their CNT reinforced composites (CNHONNs) are of interest. Most experimental studies on CNT-Ni composites were dedicated to the development and improvement of fabrication process for improving the mechanical properties [21; 22; 23; 24; 25] or to use it as functional materials [26; 27; 28; 14; 29]. [PERSON] et al. [21] fabricated CNT-reinforced nickel nanocomposites by using an innovative electrochemical co-deposition process and found that the tensile strength of CNT/Ni composite is as high as 2 GPa, which is three times that of pure nickel. [PERSON] et al. [24] processed CNT/Ni composite by a molecular-level mixing (MLM) process followed by spark plasma sintering (SPS) and the result showed that the composite exhibits a yield strength of 710 MPa, about 3.7 times that of monolithic nickel. [PERSON] et al. [25] constructed two types of CNT/Ni nanocomposites by using simple mechanical dry milling of nickel and CNT powders or MLM process as precursors followed by SPS and found that both types of nanocomposites exhibits a substantial enhancement in microhardness and tensile yield strength as compared to SPS processed pure Ni. [PERSON] et al. [26] used CNTs as a functional additive to improve the electrochemical performance of pasted nickel-foam electrodes for rechargeable alkaline nickel batteries and found that as compared with the electrode without CNTs, the electrode with 3 wt% CNT addition exhibits a higher charging efficiency, greater specific discharge capacity, higher discharge voltage, better high-rate capability and superior cycling stability. [PERSON] et al. [14] synthesized CNT/Ni hybrid nanostructured arrays (NSAs) on a stainless steel substrate through a one-step chemical-vapor-deposition (CVD) method using nullaginite NSAs as starting materials and found that the composite can be used as high-performance electrode materials for electrochemical capacitors (ECs).